CN114901710A

CN114901710A - Fluorinated copolymers and compositions and articles comprising the same

Info

Publication number: CN114901710A
Application number: CN202080091719.4A
Authority: CN
Inventors: 利萨·P·陈; 格雷格·D·达尔克; 丹尼斯·杜谢恩; 克劳斯·辛策; 马修·J·林德尔; 肖恩·M·史密斯; 阿尔内·塔勒; 迈克尔·A·扬德拉希茨
Original assignee: 3M Innovative Properties Co
Current assignee: 3M Innovative Properties Co
Priority date: 2019-12-20
Filing date: 2020-12-18
Publication date: 2022-08-12
Anticipated expiration: 2040-12-18
Also published as: US20230056130A1; US12034193B2; CN114901710B; KR20220119048A; WO2021127346A1

Abstract

The invention discloses a copolymer, which comprises a copolymer represented by the formula- [ CF ₂ ‑CF ₂ ]-a divalent unit represented by formula (i), at least one divalent unit represented by formula (i):

and at least one compound represented by the formula (II)) Independently represented divalent units:

a is-N (RF) ^a ) ₂ Or a non-aromatic 5-to 8-membered perfluorinated ring containing one or two nitrogen atoms in the ring and optionally at least one oxygen atom in the ring, each RF ^a Independently a linear or branched perfluoroalkyl group having 1 to 8 carbon atoms and optionally interrupted by at least one chain O or N atom, each Y independently is-H or-F, with the proviso that one Y can be-CF ₃ H is 0, 1 or 2, each i is independently 2 to 8, and j is 0, 1 or 2. Also provided are catalyst inks and polymer electrolyte membranes comprising the copolymers.

Description

Fluorinated copolymers and compositions and articles comprising the same

Cross Reference to Related Applications

This application claims priority to U.S. provisional application No. 62/951,469, filed on 20.12.2019, the disclosure of which is incorporated herein by reference in its entirety.

Background

Copolymers of tetrafluoroethylene and polyfluoroethyleneoxy monomers have been prepared that contain pendant sulfonyl fluoride groups. See, for example, U.S. Pat. Nos. 3,282,875(Connolly), 3,718,627(Grot), and 4,267,364 (Grot). Copolymers of fluorinated olefins and polyfluoroallyloxysulfonyl fluorides have been prepared. See, for example, U.S. patent nos. 4,273,729(Krespan) and 8,227,139 (Watakabe), and international patent application publication No. WO 00/24709 (fannham et al). Hydrolysis of the sulfonyl fluorides of these copolymers to form acid or acid salts provides ionic copolymers, which are also referred to as ionomers.

Some of the recently disclosed ionomers are said to have high oxygen permeability. See, e.g., U.S. patent application publication nos. 2017/0183435(Ino), 2013/0253157(Takami), 2013/0245219(Perry), and 2013/0252134(Takami), and U.S. patent No. 8,470,943(Watakabe), respectively.

Disclosure of Invention

A membrane electrode assembly useful in a solid polymer electrolyte fuel cell includes an electrode catalyst layer comprising a catalyst (e.g., platinum) and an ionomer. Since catalysts (e.g., platinum) are typically expensive, it may be desirable to reduce the amount of catalyst. For ionomers used in electrodes, high oxygen permeability may be desirable to minimize electrical resistance. In the ionic catalyst layer, it may be desirable to have high oxygen permeability without reducing ion conductivity.

In addition to tetrafluoroethylene and sulfonyl group-containing monomer units, the copolymers of the present disclosure include monomer units comprising a nitrogen-containing compound. The inclusion of such nitrogen-containing compounds can generally provide high oxygen permeability ionomers for electrode applications. The inclusion of nitrogen-containing compounds can also improve processability in common solvents by increasing solubility in the dispersion.

In one aspect, the present disclosure provides a copolymer comprising a copolymer having the formula- [ CF ₂ -CF ₂ ]-a divalent unit represented by the formula:

and divalent units independently represented by the formula:

in these formulae, a is 0 or 1, b is a number from 2 to 8, c is a number from 0 to 2, e is a number from 1 to 8, X is independently-F, -NZH, -NZSO ₂ (CF ₂ ) _1-6 SO ₂ X’、-NZ[SO ₂ (CF ₂ ) _d SO ₂ NZ] _1-10 SO ₂ (CF ₂ ) _d SO ₂ X', or-OZ, each Y is independently-F or-H, provided that one Y can be-CF ₃ Each Z is independently hydrogen, alkyl having up to four carbon atoms, an alkali metal cation, or a quaternary ammonium cation, A is-N (RF) ^a ) ₂ Or a non-aromatic 5-to 8-membered perfluorinated ring containing one or two nitrogen atoms in the ring and optionally at least one oxygen atom in the ring, each RF ^a Independently a linear or branched perfluoroalkyl group having 1 to 8 carbon atoms and optionally interrupted by at least one chain O or N atom, h is 0, 1 or 2, each i is independently 2 to 8, and j is 0, 1 or 2.

In another aspect, the present disclosure provides a polymer electrolyte membrane comprising the copolymer of the present disclosure.

In another aspect, the present disclosure provides a catalyst ink comprising the copolymer of the present disclosure.

In another aspect, the present disclosure provides a membrane electrode assembly comprising at least one of such a polymer electrolyte membrane or a catalyst ink.

In another aspect, the present disclosure provides a binder for an electrochemical system, the binder comprising a copolymer of the present disclosure.

In another aspect, the present disclosure provides a battery or electrode comprising such a binder.

In the present application:

terms such as "a," "an," "the," and "said" are not intended to refer to only a single entity, but include the general class of which a particular example may be used for illustration. The terms "a", "an", "the" and "the" are used interchangeably with the term "at least one".

The phrase "comprising at least one of … …" in a subsequent list is intended to include any one of the items in the list, as well as any combination of two or more of the items in the list. The phrase "at least one (of) … … of a subsequent list refers to any one item in the list or any combination of two or more items in the list.

The "alkyl group" and the prefix "alk-" are inclusive of straight and branched chain groups as well as cyclic groups. Unless otherwise indicated, an alkyl group herein has up to 20 carbon atoms. Cyclic groups may be monocyclic or polycyclic, and in some embodiments, have from 3 to 10 ring carbon atoms.

As used herein, the terms "aryl" and "arylidene" include carbocyclic aromatic rings or ring systems, for example, having 1,2, or 3 rings optionally containing at least one heteroatom (e.g., O, S, or N) in the ring, the ring being optionally substituted with up to five substituents including one or more alkyl groups having up to 4 carbon atoms (e.g., methyl or ethyl), alkoxy groups having up to 4 carbon atoms, halo (i.e., fluoro, chloro, bromo, or iodo), hydroxy, or nitro groups. Examples of aryl groups include phenyl, naphthyl, biphenyl, fluorenyl and furyl, thienyl, pyridyl, quinolyl, isoquinolyl, indolyl, isoindolyl, triazolyl, pyrrolyl, tetrazolyl, imidazolyl, pyrazolyl, oxazolyl and thiazolyl.

An "alkylidene" group is a multivalent (e.g., divalent or trivalent) form of an "alkyl" group as defined above. An "arylidene" is a multivalent (e.g., divalent or trivalent) form of an "aryl" group as defined above.

"arylalkylene" refers to the "alkylidene" moiety to which an aryl group is attached. "alkylarylene" refers to the portion of an "arylene" to which an alkyl group is attached.

The terms "perfluoro" and "perfluorinated" refer to a group in which all C-H bonds are replaced by C-F bonds.

For example, the phrase "interrupted by at least one-O-group" with respect to a perfluoroalkyl or perfluoroalkylidene group refers to a moiety having a perfluoroalkyl or perfluoroalkylidene group on both sides of the-O-group. For example, -CF ₂ CF ₂ -O-CF ₂ -CF ₂ -is a perfluoroalkylidene group interrupted by-O-.

Unless otherwise indicated, all numerical ranges include endpoints and non-integer values between endpoints (e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4,5, etc.).

Detailed Description

The copolymers of the present disclosure comprise divalent units represented by the formula: - [ CF ₂ -CF ₂ ]-. In some embodiments, the copolymer comprises at least 60 mole percent, based on the total moles of divalent units, of units represented by the formula [ CF ] ₂ -CF ₂ ]-the bivalent unit of the representation. In some embodiments, the copolymer comprises at least 65 mole%, 70 mole%, 75 mole%, 80 mole%, or 90 mole% of the compound represented by the formula- [ CF ] based on the total moles of divalent units ₂ -CF ₂ ]-the bivalent unit of the representation. The divalent unit represented by the formula [ CF ] is obtained by copolymerizing a component containing Tetrafluoroethylene (TFE) based on the total moles of the divalent unit ₂ -CF ₂ ]The divalent units represented by-are incorporated into the copolymer. In some embodiments, the component to be polymerized comprises at least 60, 65, 70, 75, 80, or 90 mole% TFE, based on the total moles of the component to be polymerized.

The copolymer according to the present disclosure comprises at least one divalent unit independently represented by the formula:

in the formula, a is 0 or 1, b is a number from 2 to 8, c is a number from 0 to 2, and e is a number from 1 to 8. In some embodiments, b is a number from 2 to 6 or from 2 to 4. At one endIn some embodiments, b is 2. In some embodiments, e is a number from 1 to 6 or from 2 to 4. In some embodiments, e is 2. In some embodiments, e is 4. In some embodiments, c is 0 or 1. In some embodiments, c is 0. In some embodiments, c is 0 and e is 2 or 4. In some embodiments, c is 0, and e is 3 to 8,3 to 6,3 to 4, or 4. In some embodiments, at least one of c is 1 or 2 or e is 3 to 8,3 to 6,3 to 4, or 4 is true. In some embodiments, when a and c are 0, then e is 3 to 8,3 to 6,3 to 4, or 4. In some embodiments, b is 3, c is 1, and e is 2. In some embodiments, b is 2 or 3, c is 1, and e is 2 or 4. In some embodiments, a, b, c, and e can be selected to provide greater than 2, at least 3, or at least 4 carbon atoms. C _e F _2e May be straight chain or branched. In some embodiments, C _e F _2e Writable (CF) ₂ ) _e It refers to a linear perfluoroalkylidene group. When C is 2, two C _b F _2b B in the groups may be independently selected. However, at C _b F _2b Within the group, those skilled in the art will understand that b is not independently selected. In addition in the formula and in any-SO that may be present ₂ In the X terminal group, X is independently F, -NZH, -NZSO ₂ (CF ₂ ) _1-6 SO ₂ X’、-NZ[SO ₂ (CF ₂ ) _d SO ₂ NZ] _1-10 SO ₂ (CF ₂ ) _d SO ₂ X' (wherein each d is independently 1 to 6,1 to 4, or 2 to 4) or-OZ. In some embodiments, X is independently-F, -NZH, or-OZ. In some embodiments, X is-NZH or-OZ. In some embodiments, X is-F or-OZ. In some embodiments, X is-OZ. In some embodiments, X is independently-NZH, -NZSO ₂ (CF ₂ ) _1-6 SO ₂ X' or-NZ [ SO ] ₂ (CF ₂ ) _d SO ₂ NZ] _1-10 SO ₂ (CF ₂ ) _d SO ₂ And X'. X' is independently-NZH or-OZ (in some embodiments, -OZ). In these implementationsIn any of the schemes, each Z is independently hydrogen, an alkyl group having up to 4,3, 2, or 1 carbon atoms, an alkali metal cation, or a quaternary ammonium cation. The quaternary ammonium cation may be substituted with any combination of hydrogen and alkyl groups, in some embodiments, the alkyl groups independently have from one to four carbon atoms. In some embodiments, Z is an alkali metal cation. In some embodiments, Z is a sodium or lithium cation. In some embodiments, Z is a sodium cation. Copolymers having divalent units represented by this formula can be prepared by copolymerizing components comprising at least one copolymer represented by the formula CF ₂ ＝CF(CF ₂ ) _a -(OC _b F _2b ) _c -O-(C _e F _2e )-SO ₂ A polyfluoroalkallyloxy compound or a polyfluoroethyleneoxy compound represented by X ", wherein a, b, c, and e are as defined above in any one of their embodiments, and each X" is independently-F, -NZH, or-OZ. Suitable polyfluoroallyloxy and polyfluoroethyleneoxy compounds of this formula include CF ₂ ＝CFCF ₂ -O-CF ₂ -SO ₂ X”、CF ₂ ＝CFCF ₂ -O-CF ₂ CF ₂ -SO ₂ X”、CF ₂ ＝CFCF ₂ -O-CF ₂ CF ₂ CF ₂ -SO ₂ X”、CF ₂ ＝CFCF ₂ -O-CF ₂ CF ₂ CF ₂ CF ₂ -SO ₂ X”、CF ₂ ＝CFCF ₂ -O-CF ₂ CF(CF ₃ )-O-(CF ₂ ) _e -SO ₂ X”、CF ₂ ＝CF-O-CF ₂ -SO ₂ X”、CF ₂ ＝CF-O-CF ₂ CF ₂ -SO ₂ X”、CF ₂ ＝CF-O-CF ₂ CF ₂ CF ₂ -SO ₂ X”、CF ₂ ＝CF-O-CF ₂ CF ₂ CF ₂ CF ₂ -SO ₂ X' and CF ₂ ＝CF-O-CF ₂ -CF(CF ₃ )-O-(CF ₂ ) _e -SO ₂ And X'. In some embodiments, the compound represented by formula CF ₂ ＝CF(CF ₂ ) _a -(OC _b F _2b ) _c -O-(C _e F _2e )-SO ₂ The compound represented by X' is CF ₂ ＝CFCF ₂ -O-CF ₂ CF ₂ -SO ₂ X”、CF ₂ ＝CF-O-CF ₂ CF ₂ -SO ₂ X”、CF ₂ ＝CFCF ₂ -O-CF ₂ CF ₂ CF ₂ CF ₂ -SO ₂ X' or CF ₂ ＝CF-O-CF ₂ CF ₂ CF ₂ CF ₂ -SO ₂ And X'. In some embodiments, the compound represented by formula CF ₂ ＝CF(CF ₂ ) _a -(OC _b F _2b ) _c -O-(C _e F _2e )-SO ₂ The compound represented by X' is CF ₂ ＝CFCF ₂ -O-CF ₂ CF ₂ -SO ₂ X”、CF ₂ ＝CFCF ₂ -O-CF ₂ CF ₂ CF ₂ CF ₂ -SO ₂ X' or CF ₂ ＝CF-O-CF ₂ CF ₂ CF ₂ CF ₂ -SO ₂ And X'. In some embodiments, the compound of formula CF ₂ ＝CF(CF ₂ ) _a -(OC _b F _2b ) _c -O-(C _e F _2e )-SO ₂ The compound represented by X' is CF ₂ ＝CFCF ₂ -O-CF ₂ CF ₂ -SO ₂ X' or CF ₂ ＝CFCF ₂ -O-CF ₂ CF ₂ CF ₂ CF ₂ -SO ₂ X”。

By the formula CF ₂ ＝CF(CF ₂ ) _a -(OC _b F _2b ) _c -O-(C _e F _2e )-SO ₂ The compound represented by X "can be prepared by a known method. For example, by formula FSO ₂ (CF ₂ ) _e-1 -C (O) F or FSO ₂ (CF ₂ ) _e -(OC _b F _2b ) _c-1 The acid fluoride represented by-C (O) F can be reacted with perfluoroallyl chloride, perfluoroallyl bromide, or perfluoroallyl fluorosulfate in the presence of potassium fluoride (as described in U.S. Pat. No. 4,273,729 (Krespan)) to produce the formula CF ₂ ＝CFCF ₂ -(OC _b F _2b ) _c -O-(C _e F _2e )-SO ₂ A compound of F. Formula CF ₂ ＝CFCF ₂ -(OC _b F _2b ) _c -O-(C _e F _2e )-SO ₂ The compound of F can be hydrolyzed with a base (e.g., an alkali metal hydroxide or ammonium hydroxide) to provide a compound of the formula CF ₂ ＝CFCF ₂ -(OC _b F _2b ) _c -O-(C _e F _2e )-SO ₃ And Z represents a compound.

In some embodiments of the copolymers of the present disclosure, at least some of the fluorinated divalent units are derived from at least one short-chain SO-containing divalent unit ₂ A vinyl ether monomer of X'. Likewise, short chains contain SO ₂ The vinyl ether monomer of X "can be a component useful for polymerization in the process according to the present disclosure. By the formula CF ₂ ＝CF-O-(CF ₂ ) ₂ -SO ₂ Short chain SO-containing compounds represented by X ″ ₂ Vinyl ether monomers of X' (e.g. of the formula [ CF ] ₂ ＝CF-O-(CF ₂ ) ₂ -SO ₃ ]M (wherein M is an alkali metal) and CF ₂ ＝CF-O-(CF ₂ ) ₂ -SO ₂ NZH) can be made by known methods. Conveniently, of the formula [ CF ₂ ＝CF-O-(CF ₂ ) ₂ -SO ₃ ]The compound of M may be represented by the formula FC (O) -CF (CF) ₃ )-O-(CF ₂ ) ₂ -SO ₂ The known compound represented by F was prepared in three steps. Such as Gronwald, o. et al; the synthesis and the application of difluoroethyl perfluorosulfonate monomer are realized; journal of fluorine chemistry, 2008, volume 129, pages 535 to 540 (Gronwald, O., et al; Synthesis of difluorethylene monomer and its application; J. fluorine chem.,2008,129,535-540) reports that acyl fluorides can be combined with a methanolic solution of sodium hydroxide to form the disodium salt, which can be dried in anhydrous diglyme and heated to effect carboxylation. FC (O) -CF (CF) ₃ )-O-(CF ₂ ) ₂ -SO ₂ F can be prepared by ring opening and derivatization of tetrafluoroethane- β -sultone as described in U.S. Pat. No. 4,962,292(Marraccini et al). By the formula CF ₂ ＝CF-O-(CF ₂ ) _a -SO ₂ The compound represented by X "may also be prepared by reacting a compound of formula CF described in U.S. Pat. No. 6,388,139(Resnick) ₂ Cl-CFCl-O-(CF ₂ ) ₂ -SO ₂ The product of the elimination of hydrogen in the compound of F is hydrolyzed and/or FSO described in U.S. Pat. No. 6,624,328(Guerra) is subjected to ₂ -(CF ₂ ) _3-4 -O-CF(CF ₃ )-COO ^- ) _p M ^+p Hydrolysis of the decarboxylated product. Formula CF ₂ ＝CF-O-(CF ₂ ) ₂ -SO ₂ NH ₂ The compounds of (a) can be prepared, for example, by reacting a cyclic sulfone with one equivalent of LHMDS, as in Uematsu, n.et al, "synthesis of novel perfluorosulfonamide monomers and their use"; journal of fluorine chemistry, 2006, volume 127, pages 1087 to 1095 (Uematsu, N., et al, "Synthesis of novel fluoroforms monomers and the application"; J. fluorine Chem.,2006,127, 1087-.

in this formula, each Y is independently-F or-H, provided that one Y can be-CF ₃ And "A" is-N (RF) ^a ) ₂ Or a non-aromatic, 5-to 8-membered, perfluorinated ring containing one or two nitrogen atoms in the ring and optionally at least one oxygen atom in the ring, each RF ^a Independently a linear or branched perfluoroalkyl group having 1 to 8 carbon atoms and optionally interrupted by at least one chain O or N atom, h is 0, 1 or 2, each i is independently 2 to 8, and j is 0, 1 or 2. C _h F _2h May be straight chain or branched. In some embodiments, h is 0; in some embodiments, h is 1. In some embodiments, i is a number from 2 to 6 or from 2 to 4. In some embodiments, i is 2 or 3. C _i F _2i May be straight chain or branched. In some embodiments, C _i F _2i Writable (CF) ₂ ) _i It refers to a linear perfluoroalkylidene group. When j is 2, two C _i F _2i I in the group may beIndependently selected. However, at C _i F _2i Within the group, those skilled in the art will understand that i is not independently selected. In some embodiments, j is 1 or 2. In some embodiments, j is 1. In some embodiments, each Y is-F. In some embodiments, A is N (RF) ^a ) ₂ Each of which is RF ^a Is a perfluoroalkyl group having up to 4 carbon atoms. In some embodiments, "a" is a non-aromatic 5-to 8-membered perfluorinated ring. In some embodiments, "a" is bonded to the copolymer chain through a nitrogen atom. "A" may be substituted with a perfluoroalkyl group. In some embodiments, "a" is a 5-or 6-membered ring, optionally substituted with a perfluoroalkyl group having 1 to 5,1 to 3, or 1 to 2 carbon atoms. In some embodiments, "a" is

Wherein each RF is independently a perfluorinated alkylidene group having 2 to 4 (in some embodiments, 2) carbon atoms, and D is a bond, -CF ₂ -, -O-, or-N-perfluoroalkyl. In these embodiments, the divalent unit may alternatively be written as

Wherein h, i and j are as defined above in any one of its embodiments. The perfluoroalkylene group RF may be linear or branched. With a branched perfluorinated alkylidene group, the ring may be substituted with a perfluoroalkyl group having 1 to 3, or 1 to 2 carbon atoms. In some embodiments, D is a bond or-CF ₂ -. In some embodiments, D is-O-. In some embodiments, "a" is

In these embodiments, the divalent unit may alternatively be written as

Wherein h, i and j are as defined above in any one of its embodiments. Copolymers having divalent units represented by this formula can be prepared by copolymerizing components comprising at least one copolymer represented by the formula CF ₂ ＝CF(CF ₂ ) _h -(OC _i F _2i ) _j A compound represented by a, wherein h, i and j are as defined above in any one of their embodiments.

From the formula CF ₂ ＝CF(CF ₂ ) _h -(OC _i F _2i ) _j Useful compounds represented by-A include perfluorinated vinyl-and allyl-substituted aminopyrrolidines, piperidines, morpholines and piperazines, such as

In these embodiments, j is 0 and h is 0, 1, or 2. These compounds can be synthesized as described, for example, in T.Abe et al chem.Lett.1989,905, JP 01070444A (Abe), JP0107445A (Abe), International patent application WO2017/106119 (Bulinski et al) and references cited therein. By the formula CF ₂ ＝CF(CF ₂ ) _h -(OC _i F _2i ) _j Other useful compounds represented by-A include perfluorinated pyrrolidine-, piperidine-, morpholine-and piperazine-substituted alkyl vinyl ethers. In these embodiments, h is 0, and j is 1 or 2, and i is as above at itAs defined in any one of these embodiments. These vinyl ethers can be synthesized as described, for example, in U.S. patent application publication No. 2014/0130713 (Costello et al) and Kamei, Zaochuan (Hayakawa) et al, 1995, vol.36, No. 14, p.2807-.

The compound described above in any of their embodiments by formula CF ₂ ＝CF(CF ₂ ) _h -(OC _i F _2i ) _j The compound represented by-a can be present in the component to be polymerized in any useful amount, in some embodiments in an amount up to 20 mole%, 15 mole%, 10 mole%, 7.5 mole%, or 5 mole%, at least 0.5 mole%, 1 mole%, 2 mole%, 3 mole%, 4 mole%, 4.5 mole%, 5 mole%, or 7.5 mole%, or in a range of 0.5 mole% to 20 mole%, 1 mole% to 20 mole%, 2 mole% to 20 mole%, or 0.5 mole% to 10 mole%, based on the total amount of polymerizable components. Thus, copolymers according to the present disclosure may include the derivative free form CF in any useful amount, in some embodiments in an amount up to 20 mole%, 15 mole%, 10 mole%, 7.5 mole%, or 5 mole%, at least 0.5 mole%, 1 mole%, 2 mole%, 3 mole%, 4 mole%, 4.5 mole%, 5 mole%, or 7.5 mole%, or in a range of 0.5 mole% to 20 mole%, 1 mole% to 20 mole%, 2 mole% to 20 mole%, or 0.5 mole% to 10 mole%, based on the total moles of divalent units ₂ ＝CF(CF ₂ ) _h -(OC _i F _2i ) _j -A represents a divalent unit of these compounds.

In some embodiments of the copolymers of the present disclosure, the copolymer comprises a divalent unit represented by the formula

In this formula, Rf is a linear or branched perfluoroalkyl group having 1 to 8 carbon atoms and optionally interrupted by one or more-O-groups, and z is 0, 1 or2, each n is independently 1 to 4, and m is 0 or 1. In some embodiments, n is 1,3, or 4, or 1 to 3, or 2 to 4. In some embodiments, when z is 2, one n is 2 and the others are 1,3 or 4. In some embodiments, when a in any of the above formulae is 1, for example, n is 1 to 4,1 to 3,2 to 3, or 2 to 4. In some embodiments, n is 1 or 3. In some embodiments, n is 1. In some embodiments, n is not 3. When z is 2, two C _n F _2n N in the groups may be independently selected. However, at C _n F _2n Within the group, those skilled in the art will appreciate that n is not independently selected. C _n F _2n May be straight chain or branched. In some embodiments, C _n F _2n Being branched, e.g. -CF ₂ -CF(CF ₃ ) -. In some embodiments, C _n F _2n Writable (CF) ₂ ) _n It refers to a linear perfluoroalkylidene group. In these cases, the divalent unit of the formula is represented by the formula

And (4) showing. In some embodiments, C _n F _2n is-CF ₂ -CF ₂ -CF ₂ -。

In some embodiments, (OC) _n F _2n ) _z from-O- (CF) ₂ ) _1-4 -[O(CF ₂ ) _1-4 ] _0-1 And (4) showing. In some embodiments, Rf is a linear or branched perfluoroalkyl group having 1 to 8 (or 1 to 6) carbon atoms optionally interrupted by up to 4,3, or 2-O-groups. In some embodiments, Rf is a perfluoroalkyl group having 1 to 4 carbon atoms optionally interrupted by one-O-group. In some embodiments, z is 0, m is 0, and Rf is a linear or branched perfluoroalkyl group having 1 to 4 carbon atoms. In some embodiments, z is 0, m is 0, and Rf is a branched perfluoroalkyl group having 3 to 8 carbon atoms. In some embodimentsIn the case, m is 1, and Rf is a branched perfluoroalkyl group having 3 to 8 carbon atoms or a linear perfluoroalkyl group having 5 to 8 carbon atoms. In some embodiments, Rf is a branched perfluoroalkyl group having 3 to 6 or 3 to 4 carbon atoms. An example of a useful perfluoroalkyl vinyl ether (PAVE) from which these divalent units, where m and z are 0, are derived is perfluoroisopropyl vinyl ether (CF) ₂ ＝CFOCF(CF ₃ ) ₂ ) Also known as iso-PPVE. Other useful PAVEs include perfluoromethyl vinyl ether, perfluoroethyl vinyl ether and perfluoropropyl vinyl ether.

Divalent unit of the formula

Where m is 0, is typically derived from perfluoroalkoxyalkylvinylethers. Suitable Perfluoroalkoxyalkylvinylethers (PAOVE) include those of the formula CF ₂ ＝CF[O(CF ₂ ) _n ] _z ORf and CF ₂ ＝CF(OC _n F _2n ) _z ORf, wherein n, z and Rf are as defined above in any one of their embodiments. Examples of suitable perfluoroalkoxyalkylvinylethers include CF ₂ ＝CFOCF ₂ OCF ₃ 、CF ₂ ＝CFOCF ₂ OCF ₂ CF ₃ 、CF ₂ ＝CFOCF ₂ CF ₂ OCF ₃ 、CF ₂ ＝CFOCF ₂ CF ₂ CF ₂ OCF ₃ 、CF ₂ ＝CFOCF ₂ CF ₂ CF ₂ CF ₂ OCF ₃ 、CF ₂ ＝CFOCF ₂ CF ₂ OCF ₂ CF ₃ 、CF ₂ ＝CFOCF ₂ CF ₂ CF ₂ OCF ₂ CF ₃ 、CF ₂ ＝CFOCF ₂ CF ₂ CF ₂ CF ₂ OCF ₂ CF ₃ 、CF ₂ ＝CFOCF ₂ CF ₂ OCF ₂ OCF ₃ 、CF ₂ ＝CFOCF ₂ CF ₂ OCF ₂ CF ₂ OCF ₃ 、CF ₂ ＝CFOCF ₂ CF ₂ OCF ₂ CF ₂ CF ₂ OCF ₃ 、CF ₂ ＝CFOCF ₂ CF ₂ OCF ₂ CF ₂ CF ₂ CF ₂ OCF ₃ 、CF ₂ ＝CFOCF ₂ CF ₂ OCF ₂ CF ₂ CF ₂ CF ₂ CF ₂ OCF ₃ 、CF ₂ ＝CFOCF ₂ CF ₂ (OCF ₂ ) ₃ OCF ₃ 、CF ₂ ＝CFOCF ₂ CF ₂ (OCF ₂ ) ₄ OCF ₃ 、CF ₂ ＝CFOCF ₂ CF ₂ OCF ₂ OCF ₂ OCF ₃ 、CF ₂ ＝CFOCF ₂ CF ₂ OCF ₂ CF ₂ CF ₃ 、CF ₂ ＝CFOCF ₂ CF ₂ OCF ₂ CF ₂ OCF ₂ CF ₂ CF ₃ 、CF ₂ ＝CFOCF ₂ CF(CF ₃ )-O-C ₃ F ₇ (PPVE-2)、CF ₂ ＝CF(OCF ₂ CF(CF ₃ )) ₂ -O-C ₃ F ₇ (PPVE-3) and CF ₂ ＝CF(OCF ₂ CF(CF ₃ )) ₃ -O-C ₃ F ₇ (PPVE-4). In some embodiments, the perfluoroalkoxyalkylvinylethers are selected from CF ₂ ＝CFOCF ₂ OCF ₃ 、CF ₂ ＝CFOCF ₂ OCF ₂ CF ₃ 、CF ₂ ＝CFOCF ₂ CF ₂ OCF ₃ 、CF ₂ ＝CFOCF ₂ CF ₂ CF ₂ OCF ₃ 、CF ₂ ＝CFOCF ₂ CF ₂ CF ₂ CF ₂ OCF ₃ 、CF ₂ ＝CFOCF ₂ CF ₂ CF ₂ OCF ₂ CF ₃ 、CF ₂ ＝CFOCF ₂ CF ₂ CF ₂ CF ₂ OCF ₂ CF ₃ 、CF ₂ ＝CFOCF ₂ CF ₂ OCF ₂ OCF ₃ 、CF ₂ ＝CFOCF ₂ CF ₂ OCF ₂ CF ₂ CF ₂ OCF ₃ 、CF ₂ ＝CFOCF ₂ CF ₂ OCF ₂ CF ₂ CF ₂ CF ₂ OCF ₃ 、CF ₂ ＝CFOCF ₂ CF ₂ OCF ₂ CF ₂ CF ₂ CF ₂ CF ₂ OCF ₃ 、CF ₂ ＝CFOCF ₂ CF ₂ (OCF ₂ ) ₃ OCF ₃ 、CF ₂ ＝CFOCF ₂ CF ₂ (OCF ₂ ) ₄ OCF ₃ 、CF ₂ ＝CFOCF ₂ CF ₂ OCF ₂ OCF ₂ OCF ₃ And combinations thereof. Many of these perfluoroalkoxyalkylvinyl ethers can be prepared according to the methods described in U.S. Pat. Nos. 6,255,536 (word et al) and 6,294,627 (word et al). In some embodiments, the PAOVE is perfluoro-3-methoxy-n-propyl vinyl ether. In some embodiments, the PAOVE is not perfluoro-3-methoxy-n-propyl vinyl ether.

The divalent unit is represented by formula

Wherein m is 1, is typically derived from at least one perfluoroalkoxyalkylallyl ether. Suitable perfluoroalkoxyalkylallyl ethers include those of the formula CF ₂ ＝CFCF ₂ (OC _n F _2n ) _z ORf, wherein n, z and Rf are as defined above in any one of their embodiments. Examples of suitable perfluoroalkoxyalkylallyl ethers include CF ₂ ＝CFCF ₂ OCF ₂ CF ₂ OCF ₃ 、CF ₂ ＝CFCF ₂ OCF ₂ CF ₂ CF ₂ OCF ₃ 、CF ₂ ＝CFCF ₂ OCF ₂ OCF ₃ 、CF ₂ ＝CFCF ₂ OCF ₂ OCF ₂ CF ₃ 、CF ₂ ＝CFCF ₂ OCF ₂ CF ₂ CF ₂ CF ₂ OCF ₃ 、CF ₂ ＝CFCF ₂ OCF ₂ CF ₂ OCF ₂ CF ₃ 、CF ₂ ＝CFCF ₂ OCF ₂ CF ₂ CF ₂ OCF ₂ CF ₃ 、CF ₂ ＝CFCF ₂ OCF ₂ CF ₂ CF ₂ CF ₂ OCF ₂ CF ₃ 、CF ₂ ＝CFCF ₂ OCF ₂ CF ₂ OCF ₂ OCF ₃ 、CF ₂ ＝CFCF ₂ OCF ₂ CF ₂ OCF ₂ CF ₂ OCF ₃ 、CF ₂ ＝CFCF ₂ OCF ₂ CF ₂ OCF ₂ CF ₂ CF ₂ OCF ₃ 、CF ₂ ＝CFCF ₂ OCF ₂ CF ₂ OCF ₂ CF ₂ CF ₂ CF ₂ OCF ₃ 、CF ₂ ＝CFCF ₂ OCF ₂ CF ₂ OCF ₂ CF ₂ CF ₂ CF ₂ CF ₂ OCF ₃ 、CF ₂ ＝CFCF ₂ OCF ₂ CF ₂ (OCF ₂ ) ₃ OCF ₃ 、CF ₂ ＝CFCF ₂ OCF ₂ CF ₂ (OCF ₂ ) ₄ OCF ₃ 、CF ₂ ＝CFCF ₂ OCF ₂ CF ₂ OCF ₂ OCF ₂ OCF ₃ 、CF ₂ ＝CFCF ₂ OCF ₂ CF ₂ OCF ₂ CF ₂ CF ₃ 、CF ₂ ＝CFCF ₂ OCF ₂ CF ₂ OCF ₂ CF ₂ OCF ₂ CF ₂ CF ₃ 、CF ₂ ＝CFCF ₂ OCF ₂ CF(CF ₃ )-O-C ₃ F ₇ And CF ₂ ＝CFCF ₂ (OCF ₂ CF(CF ₃ )) ₂ -O-C ₃ F ₇ . In some embodiments, the perfluoroalkoxyalkylallyl ether is selected from CF ₂ ＝CFCF ₂ OCF ₂ CF ₂ OCF ₃ 、CF ₂ ＝CFCF ₂ OCF ₂ CF ₂ CF ₂ OCF ₃ 、CF ₂ ＝CFCF ₂ OCF ₂ OCF ₃ 、CF ₂ ＝CFCF ₂ OCF ₂ OCF ₂ CF ₃ 、CF ₂ ＝CFCF ₂ OCF ₂ CF ₂ CF ₂ CF ₂ OCF ₃ 、CF ₂ ＝CFCF ₂ OCF ₂ CF ₂ OCF ₂ CF ₃ 、CF ₂ ＝CFCF ₂ OCF ₂ CF ₂ CF ₂ OCF ₂ CF ₃ 、CF ₂ ＝CFCF ₂ OCF ₂ CF ₂ CF ₂ CF ₂ OCF ₂ CF ₃ 、CF ₂ ＝CFCF ₂ OCF ₂ CF ₂ OCF ₂ OCF ₃ 、CF ₂ ＝CFCF ₂ OCF ₂ CF ₂ OCF ₂ CF ₂ OCF ₃ 、CF ₂ ＝CFCF ₂ OCF ₂ CF ₂ OCF ₂ CF ₂ CF ₂ OCF ₃ 、CF ₂ ＝CFCF ₂ OCF ₂ CF ₂ OCF ₂ CF ₂ CF ₂ CF ₂ OCF ₃ 、CF ₂ ＝CFCF ₂ OCF ₂ CF ₂ OCF ₂ CF ₂ CF ₂ CF ₂ CF ₂ OCF ₃ 、CF ₂ ＝CFCF ₂ OCF ₂ CF ₂ (OCF ₂ ) ₃ OCF ₃ 、CF ₂ ＝CFCF ₂ OCF ₂ CF ₂ (OCF ₂ ) ₄ OCF ₃ 、CF ₂ ＝CFCF ₂ OCF ₂ CF ₂ OCF ₂ OCF ₂ OCF ₃ 、CF ₂ ＝CFCF ₂ OCF ₂ CF ₂ OCF ₂ CF ₂ CF ₃ 、CF ₂ ＝CFCF ₂ OCF ₂ CF ₂ OCF ₂ CF ₂ OCF ₂ CF ₂ CF ₃ And combinations thereof.

Many of these perfluoroalkoxyalkylallyl ethers can be prepared, for example, according to the methods described in U.S. Pat. No. 4,349,650 (Krespan). The perfluoroalkoxyalkyl allyl ether may also contain CF in combination ₂ ＝CF-CF ₂ -OSO ₂ Cl or CF ₂ ＝CF-CF ₂ -OSO ₂ CF ₃ A polyfluorinated compound comprising at least one ketone or carboxylic acid halide or combination thereof, and fluoride ions. Comprises at least oneThe polyfluoro compound and fluoride ion of the ketone or carboxylic acid halide or combination thereof may be any of those described, for example, in U.S. Pat. No. 4,349,650 (Krespan). CF (compact flash) ₂ ＝CF-CF ₂ -OSO ₂ Cl can be conveniently passed through boron trichloride (BCl) ₃ ) And ClSO ₃ H reacts to provide B (OSO) ₂ Cl) ₃ And subsequently reacting B (OSO) ₂ Cl) ₃ And Hexafluoropropylene (HFP) as described in International patent application publication WO 2018/211457(Hintzer et al). Mixing the components to provide CF ₂ ＝CF-CF ₂ -OSO ₂ CF ₃ The component comprises M (OSO) ₂ CF ₃ ) ₃ And Hexafluoropropylene (HFP), wherein M is Al or B. Al (OSO) ₂ CF ₃ ) ₃ Commercially available, for example, from chemical suppliers such as abcr, GmbH (Karlsruhe, Germany) of carlsrue, Germany and Sigma Aldrich, Sigma-Aldrich (st. louis, Missouri), of st louis. BCl ₃ And CF ₃ SO ₃ Reaction of H can be used to provide B (OSO) ₂ CF ₃ ) ₃ . With respect to CF ₂ ＝CF-CF ₂ -OSO ₂ CF ₃ Further details of the preparation can be found in International patent application publication No. WO 2018/211457(Hintzer et al).

The vinyl ethers and allyl ethers described above in any of their embodiments may be present in the component to be polymerized in any useful amount, in some embodiments in an amount up to 20 mole%, 15 mole%, 10 mole%, 7.5 mole%, or 5 mole%, at least 3 mole%, 4 mole%, 4.5 mole%, 5 mole%, or 7.5 mole%, or in an amount in the range of 3 mole% to 20 mole%, 4 mole% to 20 mole%, 4.5 mole% to 20 mole%, 5 mole% to 20 mole%, 7.5 mole% to 20 mole%, or 5 mole% to 15 mole%, based on the total amount of polymerizable components. Thus, copolymers according to the present disclosure may comprise divalent units derived from these vinyl and allyl ethers in any useful amount, in some embodiments in an amount up to 20, 15, 10, 7.5, or 5, at least 3,4, 4.5, 5, or 7.5 mole%, or in an amount in the range of 3 to 20, 4 to 20, 4.5 to 20, 5 to 20, 7.5 to 20, or 5 to 15 mole%, based on the total moles of divalent units. In some embodiments, the copolymers of the present disclosure are free of divalent units represented by the formula:

in some embodiments of the copolymers of the present disclosure, the copolymer comprises at least one block derived from at least one of the formulae C (R) ₂ ＝CF-Rf ₂ Independently represent divalent units of a fluorinated olefin. These fluorinated divalent units are represented by the formula- [ CR ] ₂ -CFRf ₂ ]-represents. In the formula C (R) ₂ ＝CF-Rf ₂ And- [ CR ₂ -CFRf ₂ ]In (a) to (b), Rf ₂ Is fluorine or perfluoroalkyl having 1 to 8 carbon atoms, in some embodiments 1 to 3 carbon atoms, and each R is independently hydrogen, fluorine, or chlorine. Some examples of fluorinated olefins that may be used as components of the polymerization include Hexafluoropropylene (HFP), Chlorotrifluoroethylene (CTFE), and partially fluorinated olefins such as vinylidene fluoride (VDF), tetrafluoropropene (R1234yf), pentafluoropropene, and trifluoroethylene. In some embodiments, the copolymer comprises at least one of a divalent unit derived from chlorotrifluoroethylene or a divalent unit derived from hexafluoropropylene. Based on the total number of moles of divalent units, represented by the formula- [ CR ] ₂ -CFRf ₂ ]The divalent units represented by-may be present in the copolymer in any useful amount, in some embodiments in an amount up to 10 mole%, 7.5 mole%, or 5 mole%.

In some embodiments of the copolymers of the present disclosure, the copolymer is substantially free of VDF units and the component to be copolymerized is substantially free of VDF. For example, at pH above 8, dehydrofluorination of VDF can occur and can be used to exclude VDF from the components to be polymerized. By "substantially free of VDF" can mean that VDF is present in the component to be polymerized in an amount less than 1 mole% (in some embodiments, less than 0.5 mole%, 0.1 mole%, 0.05 mole%, or 0.01 mole%). "substantially free of VDF" includes the absence of VDF.

The copolymers of the present disclosure may comprise divalent units independently represented by the formula:

wherein p is 0 or 1, q is 2 to 8, r is 0 to 2, s is 1 to 8, and Z' is hydrogen, an alkali metal cation or a quaternary ammonium cation. In some embodiments, q is a number from 2 to 6 or from 2 to 4. In some embodiments, q is 2. In some embodiments, s is a number from 1 to 6 or from 2 to 4. In some embodiments, s is 2. In some embodiments, s is 4. In some embodiments, r is 0 or 1. In some embodiments, r is 0. In some embodiments, r is 0 and s is 2 or 4. In some embodiments, q is 3, r is 1, and s is 2. C _s F _2s May be straight chain or branched. In some embodiments, C _s F _2s Writable (CF) ₂ ) _s It refers to a linear perfluoroalkylidene group. When r is 2, two C _q F _2q Q in the groups may be independently selected. However, at C _q F _2q Within the group, those skilled in the art will appreciate that q is not independently selected. Each Z' is independently hydrogen, an alkali metal cation, or a quaternary ammonium cation. The quaternary ammonium cation may be substituted with any combination of hydrogen and alkyl groups, in some embodiments, the alkyl groups independently have from one to four carbon atoms. In some embodiments, Z' is an alkali metal cation. In some embodiments, Z' is a sodium or lithium cation. In some embodiments, Z' is a sodium cation. Divalent units represented by the following formula based on the total number of moles of the divalent units

The copolymer may be present in any useful amount, in some embodiments in an amount up to 10 mole%, 7.5 mole%, or 5 mole%, based on the total moles of divalent units.

The copolymers of the present disclosure may also comprise a polymer derived from formula X ₂ C＝CY’-(CW ₂ ) _m -(O) _n -R _F -(O) _o -(CW ₂ ) _p -CY’＝CX ₂ Units of diolefins are shown. In this formula, each of X, Y' and W is independently fluorine, hydrogen, alkyl, alkoxy, polyoxyalkyl, perfluoroalkyl, perfluoroalkoxy, or perfluoropolyoxyalkyl, m and p are independently integers from 0 to 15, and n, o are independently 0 or 1. In some embodiments, X, Y' and W are each independently fluorine, CF ₃ 、C ₂ F ₅ 、C ₃ F ₇ 、C ₄ F ₉ Hydrogen, CH ₃ 、C ₂ H ₅ 、C ₃ H ₇ 、C ₄ H ₉ . In some embodiments, X, Y' and W are each fluorine (e.g., as in CF) ₂ ＝CF-O-R _F -O-CF＝CF ₂ And CF ₂ ＝CF-CF ₂ -O-R _F -O-CF ₂ -CF＝CF ₂ In (1). In some embodiments, n and o are 1, and the diolefin is divinyl ether, diallyl ether, or vinyl-allyl ether. R is _F Denotes a linear or branched perfluoroalkylene or perfluoropolyoxyalkyleneene or aromatic subunit, which may be non-fluorinated or fluorinated. In some embodiments, R _F Is a perfluoroalkylene group having 1 to 12, 2 to 10, or 3 to 8 carbon atoms. The arylene group can have 5 to 14, 5 to 12, or 6 to 10 carbon atoms, and can be unsubstituted or substituted with one or more halogen, perfluoroalkyl (e.g., -CF) groups other than fluorine ₃ and-CF ₂ CF ₃ ) Perfluoroalkoxy (e.g., -O-CF) ₃ 、-OCF ₂ CF ₃ ) Perfluoropolyoxyalkyl (e.g. OCF) ₂ OCF ₃ ；-CF ₂ OCF ₂ OCF ₃ ) Fluorinated, perfluorinated or non-fluorinated phenyl or phenoxy substituted; the phenyl or phenoxy group may be substituted by one or more perfluoroalkyl groups, perfluoroalkoxy groups, perfluoropolyoxyalkyl groups, one or moreHalogen other than fluorine or combinations thereof. In some embodiments, R _F Is phenylene or monofluorophenylene, difluorophenylene, trifluorophenylene or tetrafluorophenylene, to which an ether group is bonded in the ortho-, para-or meta-position. In some embodiments, R _F Is CF ₂ ；(CF ₂ ) _q Wherein q is 2,3, 4,5, 6,7 or 8; CF ₂ -O-CF ₂ ；CF ₂ -O-CF ₂ -CF ₂ ；CF(CF ₃ )CF ₂ ；(CF ₂ ) ₂ -O-CF(CF ₃ )-CF ₂ ；CF(CF ₃ )-CF ₂ -O-CF(CF ₃ )CF ₂ (ii) a Or (CF) ₂ ) ₂ -O-CF(CF ₃ )-CF ₂ -O-CF(CF ₃ )-CF ₂ -O-CF ₂ . Diolefins may incorporate long chain branching as described in U.S. patent application publication 2010/0311906 (Lavallee et al). The diolefins described above in any of their embodiments may be present in the components to be polymerized in any useful amount, in some embodiments in an amount of up to 2 mole%, 1 mole%, or 0.5 mole%, and in an amount of at least 0.1 mole%, based on the total amount of polymerizable components.

The copolymers of the present disclosure may also comprise units derived from non-fluorinated monomers. Examples of suitable non-fluorinated monomers include ethylene, propylene, isobutylene, ethyl vinyl ether, vinyl benzoate, ethyl allyl ether, cyclohexyl allyl ether, norbornadiene, crotonic acid, alkyl crotonate, acrylic acid, alkyl acrylate, methacrylic acid, alkyl methacrylate, and hydroxybutyl vinyl ether. Any combination of these non-fluorinated monomers may be useful. In some embodiments, the component to be polymerized further comprises acrylic acid or methacrylic acid, and the copolymers of the present disclosure comprise units derived from acrylic acid or methacrylic acid.

Typically, the copolymers of the present disclosure do not include cyclic structures that include fluorinated carbon atoms in the backbone (i.e., divalent units that include such cyclic structures) such as are derived from perfluorinated dioxoles and dioxolanes. In the copolymer of the present disclosure, the nitrogen-containing compound is pendant from the main chain, and the carbon atom included in the ring does not form a part of the main chain. Because the nitrogen-containing rings are pendant from the backbone, the copolymers of the present disclosure tend to have lower glass transition temperatures than copolymers comprising cyclic structures containing fluorinated carbon atoms. Thus, films formed from the copolymers may be more flexible and less brittle than those copolymers such as those described in 2013/0253157 (rumei (Takami)), 2013/0245219(Perry), and 2013/0252134 (rumei (Takami)) and U.S. patent No. 8,470,943 (ferry (Watakabe)).

In some embodiments, for example, according to the methods described below, copolymers according to the present disclosure may be prepared from sulfonyl fluoride compounds (wherein in the above formula CF ₂ ＝CF(CF ₂ ) _a -(OC _b F _2b ) _c -O-(C _e F _2e )-SO ₂ Any of the compounds represented by X, X is F). Having a-SO ₂ Hydrolysis of the copolymer of F groups with a solution of an alkaline hydroxide (e.g., LiOH, NaOH, or KOH) provides-SO ₃ Z group which can subsequently be acidified to SO ₃ And (4) an H group. Having a-SO ₂ SO may be formed by treating the copolymers of F groups with water and steam ₃ And (4) an H group. Thus, having a-SO ₂ Copolymers of F groups (i.e., where X is F) are useful intermediates for preparing the copolymers of the present disclosure.

In some embodiments, the copolymers of the present disclosure may be prepared by a process comprising a copolymerization component comprising at least one copolymer of the formula CF ₂ ＝CF(CF ₂ ) _a -(OC _b F _2b ) _c -O-(C _e F _2e )-SO ₂ The compound represented by X', b, c and e are as defined above in any one of their embodiments. In this formula, X 'is-NZ' H or-OZ ', where each Z' is independently hydrogen, an alkali metal cation, or a quaternary ammonium cation. The quaternary ammonium cation may be substituted with any combination of hydrogen and alkyl groups, in some embodiments, the alkyl groups independently have from one to four carbon atoms. In some embodiments, Z' is an alkali metal cation. In some embodiments, Z' is a sodium or lithium cation. In some embodiments, Z' is a sodium cation. In some embodiments of the present invention, the substrate is,by the formula CF ₂ ＝CF(CF ₂ ) _a -(OC _b F _2b ) _c -O-(C _e F _2e )-SO ₂ The compound represented by X' is CF ₂ ＝CFCF ₂ -O-CF ₂ CF ₂ -SO ₃ Na。

Copolymers according to the present disclosure may have an-SO of up to 2000, 1900, 1800, or 1750 ₂ X equivalent weight. In some embodiments, the copolymer has an-SO of at least 600, 700, 800, 900, 950 or 1000 ₂ X equivalent weight. In some embodiments, the copolymer has an-SO in the range of 600 to 2000, 800 to 2000, 950 to 2000, or 1000 to 2000 ₂ X equivalent weight. In general, the-SO of the copolymer ₂ X equivalent weight means containing one mole of-SO ₂ The weight of the copolymer of the X group, wherein X is as defined above in any one of its embodiments. In some embodiments, the-SO of the copolymer ₂ X equivalent weight refers to the weight of the copolymer that will neutralize one equivalent of base. In some embodiments, the-SO of the copolymer ₂ X equivalent weight means that one mole of sulfonate groups (i.e., -SO) is contained ₃ ^- ) The weight of the copolymer (b). Reduction of-SO of copolymers ₂ X equivalent weight tends to increase the proton conductivity of the copolymer but tends to decrease its crystallinity, which may impair the mechanical properties (e.g., tensile strength) of the copolymer. Thus, the-SO of the copolymer in the fluoropolymer dispersions of the present disclosure ₂ X equivalent weight generally and advantageously provides a balance of requirements for electrical and mechanical properties of the copolymer. Thus, the-SO may be selected based on a balance of electrical and mechanical property requirements for the copolymer or ionomer ₂ X equivalent weight. In some embodiments, the-SO of the copolymer ₂ X equivalent weight means that one mole of sulfonamide group is contained (i.e., -SO) ₂ NH) weight of copolymer. Sulfonimide groups (e.g. when X is-NZSO) ₂ (CF ₂ ) _1-6 SO ₂ X' and-NZ [ SO ] ₂ (CF ₂ ) _a SO ₂ NZ] _1-10 SO ₂ (CF ₂ ) _a SO ₂ X') also serve as acid groups which can neutralize the base, as described belowDescribed in more detail. The effective equivalent weight of copolymers containing these groups can be well below 1000. Equivalent weight can be calculated from the molar ratio of monomer units in the copolymer using, for example, the formula shown in the examples below.

The copolymers of the present disclosure may have up to 30 mole%, based on the total amount of divalent units, of the formula

The bivalent unit represented. In some embodiments, the copolymer comprises up to 25 mole% or 20 mole% of these divalent units, based on the total amount of these divalent units. The components copolymerized in the methods described herein may comprise up to 30 mole%, based on the total amount of copolymerized components, of at least one of the formulae CF in any of their embodiments described above ₂ ＝CF(CF ₂ ) _a -(OC _b F _2b ) _c -O-(C _e F _2e )-SO ₂ X' or CF ₂ ＝CF(CF ₂ ) _a -(OC _b F _2b ) _c -O-(C _e F _2e )-SO ₂ And X' represents a compound. In some embodiments, the component comprises up to 25 mole% or 20 mole% of a compound of formula CF, based on the total amount of copolymerized components ₂ ＝CF(CF ₂ ) _a -(OC _b F _2b ) _c -O-(C _e F _2e )-SO ₂ X' or CF ₂ ＝CF(CF ₂ ) _a -(OC _b F _2b ) _c -O-(C _e F _2e )-SO ₂ And X' represents a compound.

The molecular weight of the copolymers of the present disclosure can be characterized by the melt viscosity or melt flow index (MFI, e.g., 265 ℃/5kg) of the copolymer variant where X is F. In some embodiments, the copolymer of the present disclosure has an MFI of at most 80 grams per 10 minutes, 70 grams per 10 minutes, 60 grams per 10 minutes, 50 grams per 10 minutes, at most 40 grams per 10 minutes, 30 grams per 10 minutes, or 20 grams per 10 minutes. In some embodiments, the copolymers of the present disclosure have an MFI of at most 15 grams per 10 minutes or at most 12 grams per 10 minutes. Good mechanical properties are achieved when the MFI is at most 80 g/10 min, 70 g/10 min, 60 g/10 min, 50 g/10 min, 40 g/10 min, 30 g/10 min, 20 g/10 min, 15 g/10 min or 12 g/10 min. The MFI of the copolymer can be adjusted to at most 80 grams per 10 minutes by adjusting the amount of initiator and/or chain transfer agent used during polymerization, both of which affect the molecular weight and molecular weight distribution of the copolymer. The MFI can also be controlled by the rate at which the initiator is added to the polymerization. Variations of the monomer composition may also affect the MFI. For the purposes of this disclosure, MFI is measured according to the test method described in the examples below. It should be noted that an MFI of about 20 grams per 10 minutes measured at 270 ℃/2.16kg will provide an MFI of 43 grams per 10 minutes measured at 265 ℃/5 kg. Generally, when measuring the MFI at 265 ℃/5kg, values exceeding twice the MFI measured at 270 ℃/2.16kg are obtained.

In some embodiments, the copolymers of the present disclosure are ionomers (e.g., when X is not F). Ionomers typically exhibit a thermal transition between a state in which ionic clusters are closely associated and a state in which the interactions between those clusters have been weakened. The transition is described as an alpha transition and the transition temperature is T (alpha). Ionomers with higher T (α 0) generally have greater mechanical integrity at high temperatures than the corresponding materials with lower T (α). Thus, to obtain a high tolerable temperature for the ionomer, a relatively high T (α) may be desired for the ionomer. In some embodiments, the copolymers of the present disclosure have an α -dispersion temperature T (α) of at least 95 ℃, 100 ℃, 105 ℃, 110 ℃, or 115 ℃. However, we have found that reducing T (α) can increase oxygen permeability, and it can be useful to select T (α) to achieve a balance of mechanical integrity and oxygen permeability. In some embodiments, the alpha-dispersion temperature [ T (alpha) ] of the copolymers of the present disclosure]At most 110 ℃, 105 ℃, or 100 ℃, or less than 100 ℃, in some embodiments at most 99.5 ℃ or 99 ℃. In some embodiments, the alpha-dispersion temperature [ T (alpha) ] of the copolymers of the present disclosure]At least room temperature (e.g., 25 ℃), and in some embodiments, at least 60 ℃,6570 deg.C, 75 deg.C, 80 deg.C, 85 deg.C, 90 deg.C, or 95 deg.C. In some embodiments, the alpha-dispersion temperature [ T (alpha) ] of the copolymers of the present disclosure]In the range of 60 ℃ to 100 ℃,70 ℃ to 100 ℃, 80 ℃ to 100 ℃,90 ℃ to 100 ℃, or 95 ℃ to 100 ℃. In some embodiments, the alpha-dispersion temperature [ T (alpha) ] of the copolymers of the present disclosure]At a temperature in the range of 60 ℃ to 99.5 ℃,70 ℃ to 99.5 ℃, 80 ℃ to 99.5 ℃,90 ℃ to 99.5 ℃, or 95 ℃ to 99.5 ℃. In some embodiments, the alpha-dispersion temperature [ T (alpha) ] of the copolymers of the present disclosure]In the range of 60 ℃ to 99 ℃,70 ℃ to 99 ℃, 80 ℃ to 99 ℃,90 ℃ to 99 ℃, or 95 ℃ to 99 ℃. In the copolymers of the present disclosure, various factors can influence [ T (α)]. For example, when a, b, c, and e are selected to provide greater than 2, at least 3, or at least 4 carbon atoms in the side chain of the sulfonyl-substituted divalent unit, a T (α) of up to 100 ℃ (e.g., in the range of 80 ℃ to 100 ℃,90 ℃ to 100 ℃, or 95 ℃ to 100 ℃) can be achieved. When m, m', n, z, Rf and Rf are selected ₁ To provide greater than 2, at least 3, or at least 4 carbon atoms and/or at least one or 2 oxygen atoms in the side chain of a divalent unit represented by the formula

T (α) may reach up to 100 ℃ (e.g., in the range of 80 ℃ to 100 ℃,90 ℃ to 100 ℃, or 95 ℃ to 100 ℃). Inclusion of more than 3 mole%, 4 mole%, 4.5 mole%, 5 mole%, or 7.5 mole% of these divalent units may be used to achieve T (α) within these ranges. In addition, cations present in the ionomer affect T (α). Thus, the T (α) of the copolymers of the present disclosure can be altered, for example, by ion exchange.

Dynamic Mechanical Analysis (DMA) is a useful tool for measuring T (α) because of the change in physical properties of the polymer that accompanies this transition. The DMA sample chamber may be configured to twist, compress, or tension. For the purposes of this disclosure, T (α) is measured by the method described in the following examples. Since T (α) varies with different cations, for the purposes of this disclosure, T (α) is understood to be T (α) when Z is hydrogen.

The glass transition temperature (Tg) is generally defined as the temperature at which an amorphous polymer or amorphous region within a polymer transitions from a glassy material (below Tg) to a rubbery material (above Tg). The gas Diffusion rate is related to the free volume in the polymer [ see, e.g., "Diffusion in polymer", massel Dekker press (New York),1996 (Diffusion in Polymers, Marcel Dekker (New York),1996), edited by p. The free volume increases with increasing temperature, especially above the Tg of the polymer. The higher the molecular transport of the gas, the greater the extent to which the operating temperature exceeds the Tg of the polymer. Thus, polymers having a relatively low Tg may be desirable for applications requiring gas diffusion. In some embodiments, in the copolymers of the present disclosure, a, b, c, and e can be selected to provide greater than 2, at least 3, or at least 4 carbon atoms in the side chain of the sulfonyl-substituted divalent unit to achieve a lower Tg. In some embodiments, the copolymer in which X is F has a Tg of less than 30 ℃, less than room temperature, or up to 25 ℃,20 ℃, 15 ℃, or 10 ℃. Since many bulk physical properties of polymers differ in the glassy versus rubbery state, various methods can be used to measure Tg. Differential Scanning Calorimetry (DSC) and dilatometry detect changes in heat capacity and thermal expansion of the polymer in two states, while methods such as thermomechanical analysis (TMA) and Dynamic Mechanical Analysis (DMA) detect differences in physical properties in the two states. For the purposes of this disclosure, Tg is measured by the method described in the examples below.

In some embodiments, the copolymers of the present disclosure have at least one of a relatively high T (α) (e.g., at least 100 ℃, 105 ℃, 110 ℃, 115 ℃, 120 ℃, or 125 ℃) or a relatively low Tg (e.g., at most 25 ℃,20 ℃, 15 ℃, or 10 ℃). In some embodiments, the copolymers of the present disclosure have at least one of a relatively low T (α) (e.g., at most 110 ℃, 105 ℃, or 100 ℃) or a relatively low Tg (e.g., at most 25 ℃,20 ℃, 15 ℃, or 10 ℃). In some embodiments, the copolymers of the present disclosure have both a relatively high T (α) (e.g., at least 100 ℃, 105 ℃, 110 ℃, 115 ℃, 120 ℃, or 125 ℃) and a relatively low Tg (e.g., at most 25 ℃,20 ℃, 15 ℃, or 10 ℃). In some embodiments, the copolymers of the present disclosure have both a relatively low T (α) (e.g., at most 110 ℃, 105 ℃, or 100 ℃) and a relatively low Tg (e.g., at most 25 ℃,20 ℃, 15 ℃, or 10 ℃).

The high oxygen permeability of the copolymers disclosed herein can be used to improve the efficiency of, for example, fuel cells. The copolymers of the present disclosure typically have useful oxygen permeability for fuel cell applications. Oxygen permeability can be measured by methods known in the art, including the time-lag method described in the examples below.

The process for preparing the copolymers may be carried out by free radical polymerization. Conveniently, in some embodiments, the method of making the copolymers disclosed herein comprises a free radical aqueous emulsion polymerization.

In some embodiments of the method of making the copolymer, a water soluble initiator (e.g., potassium permanganate or peroxysulfate) can be used to start the polymerization process. Salts of peroxysulfuric acid, such as ammonium persulfate or potassium persulfate, may be used alone or in the presence of a reducing agent such as a bisulfite or sulfinate (e.g., fluorinated sulfinate as disclosed in U.S. Pat. Nos. 5,285,002 and 5,378,782, both to Grootaert) or the sodium salt of hydroxymethanesulfinic acid (sold under the trade designation "RONGALIT" by BASF Chemical Company, New Jersey, USA, N.J.). The choice of initiator and reducing agent (if present) will affect the end groups of the copolymer. The concentration ranges of the initiator and reducing agent can vary from 0.001 to 5% by weight, based on the aqueous polymerization medium.

In some embodiments of the method of making the copolymer, the SO is generated during the polymerization process ₃ ^─ Free radical of-SO ₂ The X end groups are incorporated into the copolymers according to the present disclosure. When salts of peroxysulfuric acid are used in the presence of sulfites or bisulfites (e.g., sodium or potassium sulfite), SO is generated during the polymerization process ₃ ^─ Free radicals, thereby producing-SO ₃ ^─ An end group. It may be useful to add metal ions to catalyze or accelerate-SO ₃ ^- Formation of free radicals. By varying the stoichiometry of the sulfite or bisulfite relative to the peroxydisulfate salt, the-SO can be varied ₂ Amount of X end groups.

Most of the initiators mentioned above and any emulsifiers that can be used in the polymerization have an optimum pH range in which they show the highest efficiency. In addition, for the process according to the present disclosure, the pH may be selected such that the formula CF ₂ ＝CF(CF ₂ ) _a -(OC _b F _2b ) _c -O-(C _e F _2e )-SO ₂ The compound of X 'is polymerized in a salt form (wherein X' is an alkali metal cation or an ammonium cation), and the salt form of the copolymer is maintained. For these reasons, buffers may be useful. Buffers include phosphates, acetates or carbonates (e.g., (NH) ₄ ) ₂ CO ₃ Or NaHCO ₃ ) A buffer or any other acid or base, such as ammonia or an alkali metal hydroxide. In some embodiments, the copolymerization is carried out at a pH of at least 8, greater than 8, at least 8.5, or at least 9. The concentration ranges of initiator and buffer may vary from 0.01 to 5 wt% based on the aqueous polymerization medium. In some embodiments, an amount of ammonia is added to the reaction mixture to adjust the pH to at least 8, above 8, at least 8.5, or at least 9.

Typical chain transfer agents are for example H ₂ Lower alkanes, alcohols, ethers, esters and CH ₂ Cl ₂ Can be used to prepare copolymers and ionomers according to the present disclosure. Termination via chain transfer leads to a polydispersity of about 2.5 or less. In some embodiments of the methods according to the present disclosure, the polymerization is carried out in the absence of any chain transfer agent. Lower polydispersity can sometimes be achieved in the absence of chain transfer agents. For small conversions, recombination typically results in a polydispersity of about 1.5.

Useful polymerization temperatures may range from 20 ℃ to 150 ℃. Typically, the polymerization is carried out at a temperature in the range of 30 ℃ to 120 ℃, 40 ℃ to 100 ℃, or 50 ℃ to 90 ℃. The polymerization pressure is generally from 0.4MPa to 2.5 MPaMPa, 0.6MPa to 1.8MPa, 0.8MPa to 1.5MPa, and in some embodiments, 1.0MPa to 2.0 MPa. Fluorinated monomers such as HFP can be preloaded and fed into the reactor, as for example in "Modern Fluoropolymers", edited by John Scheirs, Willi-father-publishers, 1997, page 241 (Modern Fluoropolymers, ed. John Scheirs, Wiley-der-Fluoropolmers, ed. John Scheirs&Sons,1997, p.241). By the formula CF ₂ ＝CF(OC _n F _2n ) _z ORf and perfluoroalkoxyalkylvinylethers and the compound of formula CF ₂ ＝CFCF ₂ (OC _n F _2n ) _z The perfluoroalkoxyalkyl allyl ether represented by ORf (where n, z and Rf are as defined above in any of their embodiments) is typically liquid and can be sprayed into the reactor or added directly, evaporated or atomized.

For convenience, in some embodiments of the method of making the copolymer, the polymerization process can be conducted without an emulsifier (e.g., without a fluorinated emulsifier). Surprisingly, it has been found that even with the incorporation of liquid perfluoroalkoxyalkyl vinyl ethers or perfluoroalkoxyalkyl allyl ethers or diolefins in high amounts, fluorinated emulsifiers are not required to ensure proper incorporation of these monomers. It may be useful to synthesize a compound of formula CF ₂ ＝CF(CF ₂ ) _a -(OC _b F _2b ) _c -O-(C _e F _2e )-SO ₂ The compound represented by X "and a non-functional comonomer (e.g., perfluoroalkoxyalkylvinyl ether or perfluoroalkoxyalkylallyl ether or diolefin) are fed as a homogeneous mixture for polymerization. In some embodiments, CF ₂ ＝CF(CF ₂ ) _a -(OC _b F _2b ) _c -O-(C _e F _2e )-SO ₂ Some of F (e.g. up to 5ppm) may be hydrolysed to obtain an "in situ" emulsifier. Advantageously, the process can be carried out in the absence of any other fluorinated emulsifier.

However, in some embodiments perfluorinated or partially fluorinated emulsifiers may be useful. Generally, these fluorinated emulsifiers are present in about 0.02% to about 3% by weight relative to the polymerIs present in the range of% by weight. The polymer particles prepared with the fluorinated emulsifier typically have an average diameter in the range of about 10 nanometers (nm) to about 500nm, and in some embodiments, in the range of about 50nm to about 300nm, as determined by dynamic light scattering techniques. Examples of suitable emulsifiers include those having the formula [ R _f -O-L-COO ^- ] _i X ⁱ⁺ Wherein L represents a partially or fully fluorinated linear alkylidene group or an aliphatic hydrocarbon group, R _f Denotes a linear partially or fully fluorinated aliphatic group, or a linear partially or fully fluorinated aliphatic group interrupted by one or more oxygen atoms, X ⁱ⁺ Represents a cation having a valence i, and i is 1,2 or 3. (see, e.g., U.S. patent No. 7,671,112 to euphz (Hintzer) et al). Additional examples of suitable emulsifiers also include perfluorinated polyether emulsifiers having the formula: formula CF ₃ -(OCF ₂ ) _x -O-CF ₂ -X ', wherein X has a value of 1 to 6, and X' represents a carboxylic acid group or a salt thereof; and formula CF ₃ -O-(CF ₂ ) ₃ -(OCF(CF ₃ )-CF ₂ ) _y -O-L-Y', wherein Y has a value of 0, 1,2 or 3 and L represents a group selected from-CF (CF) ₃ )-、-CF ₂ -and-CF ₂ CF ₂ -and Y' represents a carboxylic acid group or a salt thereof. (see, e.g., U.S. patent application No. 2007/0015865 to Hintzer et al.) other suitable emulsifiers include perfluorinated polyether emulsifiers having the formula R _f -O(CF ₂ CF ₂ O) _x CF ₂ COOA, wherein R _f Is C _b F _(2b+1) (ii) a Wherein b is 1 to 4, A is a hydrogen atom, an alkali metal or NH ₄ And x is an integer of 1 to 3. (see, e.g., U.S. patent publication No. 2006/0199898 to Funaki et al). Suitable emulsifiers also include those having the formula F (CF) ₂ ) _b O(CF ₂ CF ₂ O) _x CF ₂ Perfluorinated emulsifiers of COOA, where A is a hydrogen atom, an alkali metal or NH ₄ B is an integer of 3 to 10, and x is 0 or an integer of 1 to 3. (see, e.g., U.S. patent publication to Funaki et alCloth number 2007/0117915). Additional suitable emulsifiers include fluorinated polyether emulsifiers as described in U.S. Pat. No. 6,429,258 to Morgan et al, as well as perfluorinated or partially fluorinated alkoxy acids and salts thereof, wherein the perfluoroalkyl component of the perfluoroalkoxy group has 4 to 12 carbon atoms, or 7 to 12 carbon atoms. (see, e.g., U.S. Pat. No. 4,621,116 to Morgan). Suitable emulsifiers also include those having the formula [ R _f -(O) _t -CHF-(CF ₂ ) _x -COO-] _i X ⁱ⁺ The partially fluorinated polyether emulsifier of (1), wherein R _f Denotes a partially or fully fluorinated aliphatic group optionally interrupted by one or more oxygen atoms, t is 0 or 1 and X is 0 or 1, X ⁱ⁺ Represents a cation having a valence i, and i is 1,2 or 3. (see, e.g., U.S. patent publication No. 2007/0142541 to Hintzer et al). Additional suitable emulsifiers include perfluorinated or partially fluorinated ether-containing emulsifiers as described in U.S. patent publications 2006/0223924, 2007/0060699 and 2007/0142513, each to Tsuda et al, and 2006/0281946 to Morita et al. Fluoroalkyl groups may also be used, for example perfluoroalkyl carboxylic acids having 6 to 20 carbon atoms and salts thereof, such as Ammonium Perfluorooctanoate (APFO) and ammonium perfluorononanoate (see, e.g., U.S. patent No. 2,559,752 to Berry). Conveniently, in some embodiments, the method of making a copolymer according to the present disclosure may be carried out in the absence of any one of these emulsifiers or any combination thereof.

If a fluorinated emulsifier is used, the emulsifier can be removed or recycled from the fluoropolymer latex, if desired, as described in U.S. Pat. No. 5,442,097 to Obermeier et al, U.S. Pat. No. 6,613,941 to Felix et al, U.S. Pat. No. 6,794,550 to Hintzer et al, U.S. Pat. No. 6,706,193 to Burkard et al, and U.S. Pat. No. 7,018,541 to Hintzer et al.

In some embodiments, the resulting copolymer latex is purified by at least one of an anion exchange process or a cation exchange process to remove functional comonomers, anions, and/or cations (described below) prior to coagulation or spray drying. As herein describedAs used, the term "purification" refers to at least partial removal of impurities, whether or not complete removal. Anionic species that may constitute impurities include, for example, fluoride, anionic residues from surfactants and emulsifiers (e.g., perfluorooctanoate), and anionic groups of the formula CF ₂ ＝CF(CF ₂ ) _a -(OC _b F _2b ) _c -O-(C _e F _2e )-SO ₂ And X' represents a residual compound. It should be noted, however, that it may not be desirable to remove ionic fluoropolymer from the dispersion. Useful anion exchange resins typically include polymers (typically crosslinked) having a plurality of cationic groups (e.g., quaternary alkyl ammonium groups) paired with various anions (e.g., halide or hydroxide ions). When contacted with the fluoropolymer dispersion, the anionic impurities in the dispersion become associated with the anion exchange resin. After the anion exchange step, the resulting anion-exchanged dispersion is separated from the anion exchange resin, for example by filtration. It has been reported in U.S. patent 7,304,101(Hintzer et al) that the anion hydrolyzed fluoropolymer does not appreciably fix to the anion exchange resin, which can lead to coagulation and/or material loss. Anion exchange resins are commercially available from a variety of sources. If the anion exchange resin is not in the hydroxide form, it may be at least partially or completely converted to the hydroxide salt form prior to use. This is usually accomplished by treating the anion exchange resin with aqueous ammonia or sodium hydroxide solution. Generally, better yields are obtained using gel-type anion exchange resins than with macroporous anion exchange resins.

Examples of cationic impurities resulting from the above-described polymerization include one or more alkali metal cations (e.g., Li) ⁺ 、Na ⁺ 、K ⁺ ) Ammonium, quaternary alkylammonium, alkaline earth metal cations (e.g., Mg) ²⁺ 、Ca ²⁺ ) Manganese cation (e.g., Mn) ²⁺ ) And a group III metal cation. Useful cation exchange resins include polymers (typically crosslinked) having multiple pendant anionic or acidic groups, such as, for example, polysulfonates or polysulfonic acids, polycarboxylates or polycarboxylic acids. Useful sulfonic acid cation exchange resinsExamples of the exchange resin include sulfonated styrene-divinylbenzene copolymer, sulfonated crosslinked styrene polymer, phenol-formaldehyde-sulfonic acid resin, and benzene-formaldehyde-sulfonic acid resin. The carboxylic acid cation exchange resin is an organic acid cation exchange resin, such as a carboxylic acid cation exchange resin. Cation exchange resins are commercially available from a variety of sources. Cation exchange resins are generally commercially available in their acid or sodium salt form. If the cation exchange resin is not in the acid form (i.e., protonated form), it may be at least partially or completely converted to the acid form in order to avoid the generally undesirable introduction of other cations into the dispersion. This conversion to the acid form can be achieved by means well known in the art, for example by treatment with any sufficiently strong acid.

If the purification of the copolymer latex is carried out using both anion exchange and cation exchange processes, the anion exchange resin and the cation exchange resin may be used alone or in combination as in the case of, for example, a mixed resin bed having both anion exchange resin and cation exchange resin.

In order to coagulate the obtained copolymer latex, any coagulant which is generally used for coagulation of a fluoropolymer latex may be used, and may be, for example, a water-soluble salt (e.g., calcium chloride, magnesium chloride, aluminum chloride, or aluminum nitrate), an acid (e.g., nitric acid, hydrochloric acid, or sulfuric acid), or a water-soluble organic liquid (e.g., ethanol or acetone). The amount of the coagulant to be added may be in the range of 0.001 to 20 parts by mass, for example, in the range of 0.01 to 10 parts by mass per 100 parts by mass of the latex. Alternatively or in addition, the latex may be frozen, for example with a homogenizer, for coagulation or mechanical coagulation, as described in us patent 5,463,021(Beyer et al). Alternatively or in addition, the latex may be coagulated by the addition of a polycation. It can also be used to avoid acids and alkaline earth metal salts as coagulants to avoid metal contamination. To avoid complete coagulation and any contamination from the coagulant, spray drying the latex after polymerization and optional ion exchange purification can be used to provide the solid copolymer.

The coagulated copolymer may be collected by filtration and washed with water. The washing water may be, for example, ion-exchanged water, pure water, or ultrapure water. The amount of the washing water may be 1 to 5 times by mass of the copolymer or ionomer, whereby the amount of the emulsifier attached to the copolymer can be sufficiently reduced by one washing.

The copolymer produced may have a metal ion content of less than 50ppm, in some embodiments less than 25ppm, less than 10ppm, less than 5ppm, or less than 1 ppm. In particular, the content of metal ions such as alkali metals, alkaline earth metals, heavy metals (e.g., nickel, cobalt, manganese, cadmium, and iron) can be reduced. To achieve a metal ion content of less than 50ppm, 25ppm, 10ppm, 5ppm or 1ppm, the polymerization can be carried out in the absence of added metal ions. For example, potassium persulfate, a common replacement initiator or co-initiator for ammonium persulfate, is not used, and the mechanical and freeze coagulation described above can be used instead of coagulation with metal salts. Organic initiators such as those disclosed in U.S. Pat. No. 5,182,342(Feiring et al) may also be used. To achieve such low ion content, ion exchange may be used, as described above, and the water used for polymerization and washing may be deionized water.

The metal ion content of the copolymer can be measured by flame atomic absorption spectroscopy after the copolymer is burned and the residue is dissolved in an acidic aqueous solution. For potassium as the analyte, the lower detection limit is less than 1 ppm.

In some embodiments of the method of making the copolymer, the free radical polymerization may also be carried out by suspension polymerization. Suspension polymerization will generally produce particle sizes of up to a few millimeters.

Methods for preparing the copolymers disclosed herein can include including SO-containing ₂ Vinyl and allyl ethers of F (e.g. CF) ₂ ＝CF(CF ₂ ) _a -(OC _b F _2b ) _c -O-(C _e F _2e )-SO ₂ F) Copolymerizing the components (a), separating the solids from the polymer dispersion, hydrolyzing the polymer, optionally purifying the polymer by ion exchange purification, and drying the resulting polymer. In some embodiments, a method of making a copolymer comprises reacting a copolymer comprising a copolymer of formula CF ₂ ＝CF(CF ₂ ) _a -(OC _b F _2b ) _c -O-(C _e F _2e )-SO ₂ Copolymerization of the components of at least one compound represented by X', optionally purification of the polymer by ion exchange purification, and spray drying of the resulting dispersion. The process conveniently eliminates the steps of separating the solid polymer and hydrolysis, resulting in a more efficient and cost effective process.

The component to be polymerized in the process according to the present disclosure may comprise more than one compound of the formula CF ₂ ＝CF(CF ₂ ) _a -(OC _b F _2b ) _c -O-(C _e F _2e )-SO ₃ And Z represents a compound. When more than one compound of formula CF is present ₂ ＝CF(CF ₂ ) _a -(OC _b F _2b ) _c -O-(C _e F _2e )-SO ₃ Z, each of a, b, c, e and Z may be independently selected. In some of these embodiments, each Z is independently an alkali metal cation or a quaternary ammonium cation.

In some cases, from formula CF ₂ ＝CF(CF ₂ ) _a -(OC _b F _2b ) _c -O-(C _e F _2e )-SO ₃ The compound represented by Z is not of the formula CF ₂ ＝CF(CF ₂ ) _a -(OC _b F _2b ) _c -O-(C _e F _2e )-SO ₂ The compound represented by F is prepared in situ. In some embodiments, the component to be polymerized in the processes disclosed herein is substantially free of a compound of the formula CF ₂ ＝CF(CF ₂ ) _a -(OC _b F _2b ) _c -O-(C _e F _2e )-SO ₂ And F represents a compound. In this regard, "substantially free of a compound of formula CF ₂ ＝CF(CF ₂ ) _a -(OC _b F _2b ) _c -O-(C _e F _2e )-SO ₂ The compound represented by F "can mean that the component to be polymerized in the process disclosed herein is free of compounds represented by the formula CF ₂ ＝CF(CF ₂ ) _a -(OC _b F _2b ) _c -O-(C _e F _2e )-SO ₂ The compound represented by F, or such compound, is present in an amount of up to 5 mole%, 4 mole%, 3 mole%, 2 mole%, 1 mole%, 0.5 mole%, 0.1 mole%, 0.05 mole%, or 0.01 mole%, based on the total amount of the components.

In other embodiments, the copolymers of the present disclosure may be prepared by reacting a copolymer of the formula CF ₂ ＝CF(CF ₂ ) _a -(OC _b F _2b ) _c -O-(C _e F _2e )-SO ₂ The compound represented by F is copolymerized with other fluorinated monomers to produce the same, as described above in any of their embodiments. In these embodiments, CF ₂ ＝CF(CF ₂ ) _a -(OC _b F _2b ) _c -O-(C _e F _2e )-SO ₂ Some of F (e.g. up to 5ppm) may be hydrolysed to obtain an "in situ" emulsifier as described above.

With inorganic initiators (e.g. persulphates, KMnO) ₄ Etc.) fluoropolymers obtained by aqueous emulsion polymerization typically have a high number of unstable carbon-based end groups (e.g., more than 200-COOM or-COF end groups/10 ⁶ Carbon atoms, wherein M is hydrogen, a metal cation or NH ₂ ). For fluorinated ionomers useful, for example, in electrochemical cells, this effect naturally increases as sulfonate equivalent weight decreases. These carbonyl end groups are susceptible to attack by peroxide radicals, which reduces the oxidative stability of the fluorinated ionomer. During operation of a fuel cell, electrolyzer or other electrochemical cell, peroxides can be formed. This degrades the fluorinated ionomer and correspondingly shortens the operating life of a given electrolyte membrane.

When polymerized, the copolymers of the present disclosure may have up to 400-COOM and-COF end groups per 10 ⁶ Carbon atoms, wherein M is independently an alkyl group, a hydrogen atom, a metal cation, or a quaternary ammonium cation. Advantageously, in some embodiments, copolymers according to the present disclosure have up to 200 unstable end groups/10 ⁶ Carbon atoms. The labile end group is a-COOM or-COF group, where M is an alkyl group, a hydrogen atom, a metal cation, or a quaternary ammonium cation. In some casesIn embodiments, the copolymer has up to 150, 100, 75, 50, 40, 30, 25, 20, 15, or 10 unstable end groups per 10 ⁶ Carbon atoms. The number of unstable end groups can be determined by Fourier transform infrared spectroscopy using the methods described below. In some embodiments, when polymerized, copolymers according to the present disclosure have up to 50 (in some embodiments up to 40, 30, 25, 20, 15, or 10) unstable end groups/10 ⁶ Carbon atoms.

Copolymers according to some embodiments of the present disclosure have-SO ₂ And (4) an X end group. As described above, -SO ₂ The X end groups can be formed by generating SO during the polymerization process ₃ ^─ Free radicals are introduced into the copolymer according to the present disclosure.

In some embodiments, reducing the number of unstable end groups can be achieved by conducting the polymerization in the presence of a salt or pseudohalide in the process disclosed above, as described in U.S. patent No. 7,214,740 (rohas et al). Suitable salts may include chloride, bromide, iodide or cyanide anions, as well as sodium, potassium or ammonium cations. The salt used for free radical polymerization may be a homogeneous salt or a blend of different salts. Examples of useful pseudohalides are nitrile-containing compounds, which provide nitrile end groups. Pseudohalide nitrile-containing compounds have one or more nitrile groups and function in the same manner as compounds in which the nitrile groups are substituted with halogens. Examples of suitable pseudohalide nitrile-containing compounds include NC-CN, NC-S-CN, NCs-CN, Cl-CN, Br-CN, I-CN, NCN ═ NCN, and combinations thereof. During free radical polymerization, the reactive atoms/groups of the salt or nitrile groups of the pseudohalide are chemically bonded to at least one end of the backbone of the fluoropolymer. This provides CF ₂ Y ¹ End groups other than carbonyl end groups, in which Y is ¹ Is chlorine, bromine, iodine or nitrile. For example, if the free radical polymerization is carried out in the presence of a KCl salt, at least one of the provided end groups will be-CF ₂ Cl end groups. Alternatively, if the free radical polymerization is carried out in the presence of NC — CN pseudohalides, at least one of the provided end groups will be-CF ₂ And a CN end group.

Post-fluorination with fluorine gas can also be used to treat unstable end groups and any concomitant degradation. Post-fluorination of the fluoropolymer may be by-COOH, amide, hydride, -COF, -CF ₂ Y ¹ And other non-perfluorinated end groups or-CF ═ CF ₂ Conversion to-CF ₃ An end group. Post-fluorination may be carried out in any convenient manner. Post-fluorination may conveniently be carried out at a temperature between 20 ℃ and 250 ℃, in some embodiments in the range 150 ℃ to 250 ℃ or 70 ℃ to 120 ℃ and a pressure of 10KPa to 1000KPa, with a nitrogen/fluorine gas mixture ratio of 75-90: 25-10. The reaction time may range from about four hours to about 16 hours. Under these conditions, the least stable carbon-based end groups are removed, however-SO ₂ The X group is largely retained and converted to-SO ₂ And F group. In some embodiments, when the above non-fluorinated monomers are used as monomers in the polymerization reaction or when the copolymers according to the present disclosure comprise divalent units independently represented by the formula:

as hereinbefore described in any of their embodiments.

The above-mentioned terminal group-CF ₂ Y ¹ Group Y in (1) ¹ Is reactive with fluorine gas, which reduces the time and energy required to post-fluorinate the copolymer in these embodiments. We have also found that the presence of alkali metal cations in the copolymer increases the rate of decomposition of the unstable carboxylic acid end groups and therefore, if desired, results in an easier, faster and cheaper subsequent post-fluorination step.

For in which-SO ₂ The X group being-SO ₂ Copolymers of F groups that can be treated with amines (e.g., ammonia) to provide sulfonamides (e.g., having-SO) ₂ NH ₂ A group). Made in this way or by using CF in the components polymerized as described above ₂ ＝CFCF ₂ -(OC _b F _2b ) _c -O-(CF ₂ ) _e -SO ₂ NH ₂ The prepared sulfonamide can be further reacted with a multifunctional sulfonyl fluoride or sulfonyl chloride compound. Examples of the polyfunctional compound which can be used include 1,1,2, 2-tetrafluoroethyl-1, 3-disulfonyl fluoride; 1,1,2,2,3, 3-hexafluoropropyl-1, 3-disulfonyl fluoride; 1,1,2,2,3,3,4, 4-octafluorobutyl-1, 4-disulfonyl fluoride; 1,1,2,2,3,3,4,4,5, 5-perfluoropentyl-1, 5-disulfonyl fluoride; 1,1,2, 2-tetrafluoroethyl-1, 2-disulfonyl chloride; 1,1,2,2,3, 3-hexafluoropropyl-1, 3-disulfonyl chloride; 1,1,2,2,3,3,4, 4-octafluorobutyl-1, 4-disulfonyl chloride; and 1,1,2,2,3,3,4,4,5, 5-perfluoropentyl-1, 5-disulfonyl chloride. After hydrolysis of the sulfonyl halide groups, the resulting copolymer (where X is-NZSO) ₂ (CF ₂ ) _1-6 SO ₃ Z) may have a higher number of ionic groups than the copolymer when polymerized. Therefore, the number of ionic groups can be increased and the equivalent weight can be reduced without affecting the main chain structure of the copolymer. In addition, the use of an insufficient amount of polyfunctional sulfonyl fluoride or sulfonyl chloride compound can result in cross-linking of the polymer chains, which can be used in some cases to improve durability (e.g., for copolymers having low equivalent weight). Additional details can be found, for example, in U.S. patent application publication 20020160272(Tanaka et al). To prevent such crosslinking, if desired, with-SO ₂ NH ₂ Copolymers of the radicals may be used of the formula FSO ₂ (CF ₂ ) _1-6 SO ₃ And H, which can be prepared by hydrolysis of any of the above-mentioned polyfunctional sulfonyl fluorides or sulfonyl chlorides with an equivalent amount of water in the presence of a base (e.g., N-Diisopropylethylamine (DIPEA)), as described in JP 2011-. Having a-SO ₂ NH ₂ Copolymers of radicals of formula FSO ₂ (CF ₂ ) _a [SO ₂ NZSO ₂ (CF ₂ ) _a ] _1- ₁₀ SO ₂ F or FSO ₂ (CF ₂ ) _a [SO ₂ NZSO ₂ (CF ₂ ) _a ] _1-10 SO ₃ H, wherein each a is independently 1 to 6,1 to 4, or 2 to 4. To prepare the polysulfonimide, a sulfonyl halide monomer (e.g.,any of those described above) and of the formula H ₂ NSO ₂ (CF ₂ ) _a SO ₂ NH ₂ The sulfonamide monomers represented are reacted in a molar ratio of (k +1)/k, wherein k represents the number of moles of sulfonamide monomers and k +1 represents the number of moles of sulfonyl halide monomers. The reaction can be carried out, for example, in the presence of a base, at 0 ℃ in a suitable solvent (e.g., acetonitrile). The sulfonyl halide monomer and sulfonamide monomer can have the same or different a values, resulting in the same or different a values for each repeat unit. The resulting product (e.g., FSO) ₂ (CF ₂ ) _a [SO ₂ NZSO ₂ (CF ₂ ) _a ] _1-10 SO ₂ F) Can be treated with one equivalent of water in the presence of a base such as N, N-Diisopropylethylamine (DIPEA) to provide, for example, FSO ₂ (CF ₂ ) _a [SO ₂ NZSO ₂ (CF ₂ ) _a ] _1-10 SO ₃ H, as described in JP 2011-one 40363.

In other embodiments, wherein-SO ₂ The X group being-SO ₂ Copolymers of F groups may be substituted with small molecule sulfonamides such as those of the formula NH ₂ SO ₂ (CF ₂ ) _1-6 SO ₃ Z (wherein Z is as defined above in any one of its embodiments) to provide-SO ₂ NHSO ₂ (CF ₂ ) _1-6 SO ₃ And Z group. According to the process described in U.S. Pat. No. 4,423,197(Behr), from formula NH ₂ SO ₂ (CF ₂ ) _1-6 SO ₃ The compound represented by Z can be synthesized by reacting a cyclic perfluorodisulfonic acid anhydride with an amine. This can also provide copolymers with very low equivalent weights.

Some conventional fluoropolymers may be difficult to disperse. A technique that can be used to disperse the fluoropolymer in the desired medium is to increase the concentration of the diluted dispersion of fluoropolymer. For example, U.S. patent application publication 2017/0183435(Ino) reports that a fluoropolymer electrolyte solution is prepared by heating a solid fluoropolymer electrolyte in a solution of 50 wt% aqueous ethanol in a 160 ℃ autoclave while stirring for five hours to obtain a fluoropolymer electrolyte solution having a solid concentration of 5 wt%. Concentration under reduced pressure provided a fluoropolymer electrolyte solution having a solid concentration of 20% by weight.

In contrast, the copolymers disclosed herein can generally be directly dispersed in a solution of water and organic solvent at a concentration of at least 10, 15, 20, or 25 weight percent without the need for incremental concentration. In some embodiments, the copolymers disclosed herein can be directly dispersed in a solution of water and organic solvent at a concentration of up to 30, 40, or 50 weight percent without the need for incremental concentration. Useful methods include combining components comprising water, organic solvent, and at least 10 weight percent of the copolymer of the present disclosure, based on the total weight of the components, and mixing the components at ambient temperature and pressure to produce the fluoropolymer dispersion. In this method, it is understood that combining components comprising at least 10 wt% of copolymer, based on the total weight of the components, refers to the concentration of copolymer when the components are initially combined (e.g., when an organic solvent is first added to an aqueous dispersion of fluoropolymer) prior to any agitation of the combined components. In some embodiments of the method, X is OZ and Z is hydrogen. Examples of suitable organic solvents that can be used to prepare fluoropolymer dispersions of copolymers of the present disclosure include: lower alcohols (e.g., methanol, ethanol, isopropanol, N-propanol), polyols (e.g., ethylene glycol, propylene glycol, glycerol), ethers (e.g., tetrahydrofuran and dioxane), diglyme, polyethylene glycol ethers, ether acetates, acetonitrile, acetone, dimethyl sulfoxide (DMSO), N Dimethylacetamide (DMA), ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, N-Dimethylformamide (DMF), N-methylpyrrolidone (NMP), dimethylimidazolidinone, butyrolactone, hexamethylphosphoric triamide (HMPT), isobutyl methyl ketone, sulfolane, and combinations thereof. In some embodiments, the copolymer, water, and organic solvent may be heated at a temperature of up to 100 ℃,90 ℃, 80 ℃,70 ℃, 60 ℃, 50 ℃, or 40 ℃ at a pressure of up to 0.2MPa or 0.15 MPa. Advantageously, the fluoropolymer dispersion can also be prepared at ambient temperature and pressure.

The copolymers of the present disclosure are useful, for example, in the manufacture of catalyst inks and polymer electrolyte membranes for use in fuel cells or other electrolytic cells. A Membrane Electrode Assembly (MEA) is the central element of a proton exchange membrane fuel cell, such as a hydrogen fuel cell. Fuel cells are electrochemical cells that produce usable electrical energy through the catalytic combination of a fuel, such as hydrogen, and an oxidant, such as oxygen. A typical MEA includes a Polymer Electrolyte Membrane (PEM), also known as an Ion Conductive Membrane (ICM), which serves as a solid electrolyte. One face of the PEM is in contact with an anode electrode layer and the opposite face is in contact with a cathode electrode layer. Each electrode layer contains an electrochemical catalyst, which typically comprises platinum metal. Gas Diffusion Layers (GDLs) facilitate the transport of gases to and from the anode and cathode electrode materials and conduct electrical current. The GDL may also be referred to as a Fluid Transport Layer (FTL) or a diffuser/current collector (DCC). The anode and cathode electrode layers may be applied to the GDL in the form of a catalyst ink, and the resulting coated GDL sandwiched with a PEM to form a five-layer MEA. Alternatively, the anode and cathode electrode layers may be applied to opposite sides of the PEM in the form of a catalyst ink, and the resulting Catalyst Coated Membrane (CCM) sandwiched with two GDLs to form a five-layer MEA. Details regarding the preparation of catalyst inks and their use in membrane modules can be found, for example, in U.S. patent publication 2004/0107869 (Velamarkanni et al). In a typical PEM fuel cell, protons are formed at the anode via oxidation of hydrogen, and transported across the PEM to the cathode to react with oxygen, causing current to flow in an external circuit connecting the electrodes. The PEM forms a durable, non-porous, non-conductive mechanical barrier between the reactant gases, but it also readily transmits H ⁺ Ions.

The copolymers of the present disclosure can be used as and/or to prepare catalyst ink compositions. In some embodiments, the copolymer (e.g., as a component of the fluoropolymer dispersion described above) may be combined with catalyst particles (e.g., metal particles or metal-on-carbon particles). A variety of catalysts may be useful. Carbon supported catalyst particles are typically used. Typical carbon-supported catalyst particles are 50 to 90 weight percent carbon and 10 to 50 weight percent catalyst metal, which typically comprises platinum as the cathode and 2:1 weight ratio of platinum and ruthenium as the anode. However, other metals may be useful, such as gold, silver, palladium, iridium, rhodium, ruthenium, iron, cobalt, nickel, chromium, tungsten, manganese, vanadium, and alloys thereof. To make an MEA or CCM, the catalyst may be applied to the PEM by any suitable means, including both manual and mechanical methods, including hand brushing, notch bar coating, fluid bearing die coating, wire-wound rod coating, fluid bearing coating, slot-fed knife coating, three-roll coating, or decal transfer. The coating can be achieved in one application or in multiple applications. Advantageously, the copolymers according to the present disclosure can be used to prepare catalyst layers having one applied coating. The catalyst ink may be applied directly to the PEM or GDL, or the catalyst ink may be applied to a transfer substrate, dried, and then applied to the PEM or FTL as a decal.

In some embodiments, the catalyst ink comprises the copolymer disclosed herein in a concentration of at least 10 wt%, 15 wt%, or 20 wt%, and at most 30 wt%, based on the total weight of the catalyst ink. In some embodiments, the catalyst ink comprises catalyst particles in an amount of at least 10 wt%, 15 wt%, or 20 wt% and at most 50 wt%, 40 wt%, or 30 wt%, based on the total weight of the catalyst ink. The catalyst particles may be added to a fluoropolymer dispersion prepared as described above in any of its embodiments. The resulting catalyst ink can be mixed, for example, by heating. For example, the percent solids in the catalyst ink can be selected to achieve a desired rheological profile. Examples of suitable organic solvents that may be used for inclusion in the catalyst ink include lower alcohols (e.g., methanol, ethanol, isopropanol, N-propanol), polyols (e.g., ethylene glycol, propylene glycol, glycerol), ethers (e.g., tetrahydrofuran and dioxane), diglyme, polyethylene glycol ethers, ether acetates, acetonitrile, acetone, dimethyl sulfoxide (DMSO), N Dimethylacetamide (DMA), ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, N-Dimethylformamide (DMF), N-methylpyrrolidone (NMP), dimethylimidazolidinone, butyrolactone, hexamethylphosphoric triamide (HMPT), isobutyl methyl ketone, sulfolane, and combinations thereof. In some embodiments, the catalyst ink contains 0 to 50 wt% lower alcohol and 0 to 20 wt% polyol. In addition, the ink may contain 0% to 2% of a suitable dispersant.

In some embodiments, the copolymers of the present disclosure may be used to prepare polymer electrolyte membranes. The copolymer can be formed into a polymer electrolyte membrane by any suitable method, including casting, molding, and extrusion. Typically, the membrane is cast from a fluoropolymer dispersion (e.g., those described above in any of their embodiments) and then dried, annealed, or both. The copolymer may be cast from a suspension. Any suitable casting method may be used, including bar coating, spray coating, slit coating, and brush coating. After formation, the film may be annealed, typically at a temperature of 120 ℃ or greater, more typically 130 ℃ or greater, and most typically 150 ℃ or greater. In some embodiments of the method according to the present disclosure, the polymer electrolyte membrane may be obtained by: obtaining the copolymer in the form of a fluoropolymer dispersion, optionally purifying the dispersion by ion exchange purification, and concentrating the dispersion to produce a membrane. Generally, if fluoropolymer dispersions are to be used to form a film, the concentration of copolymer is advantageously high (e.g., at least 20, 30, or 40 weight percent). Water-miscible organic solvents are typically added to facilitate film formation. Examples of water-miscible solvents include lower alcohols (e.g., methanol, ethanol, isopropanol, N-propanol), polyols (e.g., ethylene glycol, propylene glycol, glycerol), ethers (e.g., tetrahydrofuran and dioxane), ether acetates, acetonitrile, acetone, dimethyl sulfoxide (DMSO), N Dimethylacetamide (DMA), ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, N-Dimethylformamide (DMF), N-methylpyrrolidone (NMP), dimethylimidazolidinone, butyrolactone, hexamethylphosphoric triamide (HMPT), isobutyl methyl ketone, sulfolane, and combinations thereof.

The present disclosure provides a membrane electrode assembly comprising at least one of a catalyst ink comprising a copolymer of the present disclosure or a polymer electrolyte membrane comprising a copolymer of the present disclosure. In some embodiments, the polymer electrolyte membrane and the catalyst ink use embodiments of the copolymers disclosed herein. The catalyst ink and the polymer electrolyte membrane may use the same or different copolymers. In some embodiments, the catalyst ink comprises a copolymer of the present disclosure, and the polymer electrolyte membrane comprises a conventional copolymer (e.g., a copolymer that does not comprise one or more divalent units independently represented by the formula:

in some embodiments, the polymer electrolyte membrane is prepared from the copolymers of the present disclosure, and the catalyst ink comprises a conventional copolymer (e.g., a copolymer that does not comprise one or more divalent units independently represented by the formula:

in some embodiments of the polymer electrolyte membrane of the present disclosure, a salt of at least one of cerium, manganese, or ruthenium, or one or more cerium oxide or zirconium oxide compounds, is added to the acid copolymer prior to membrane formation. Typically, the salt of cerium, manganese, or ruthenium and/or cerium or zirconium oxide compound is thoroughly mixed with or dissolved within the copolymer to achieve a substantially uniform distribution.

The salt of cerium, manganese, or ruthenium may comprise any suitable anion, including chloride, bromide, hydroxide, nitrate, sulfonate, acetate, phosphate, and carbonate. More than one anion may be present. Other salts may be present, including salts comprising other metal cations or ammonium cations. When cation exchange is performed between the transition metal salt and the acid form ionomer, it may be desirable to remove the acid formed by the combination of the liberated proton and the original salt anion. Thus, it is possible to provideIt may be useful to use anions that generate volatile or soluble acids, such as chloride or nitrate. The manganese cation may be in any suitable oxidation state, including Mn ²⁺ 、Mn ³⁺ And Mn ⁴⁺ But most typically Mn ²⁺ . The ruthenium cation may be in any suitable oxidation state, including Ru ³⁺ And Ru ⁴⁺ But most typically Ru ³⁺ . The cerium cation may be in any suitable oxidation state, including Ce ³⁺ And Ce ⁴⁺ . While not wishing to be bound by theory, it is believed that the cerium, manganese, or ruthenium cations continue to be present in the polymer electrolyte because they interact with H in the anionic groups of the polymer electrolyte ⁺ Ion exchanged and associated with those anionic groups. Furthermore, it is believed that multivalent cerium, manganese, or ruthenium cations can form crosslinks between anionic groups of the polymer electrolyte, further increasing the stability of the polymer. In some embodiments, the salt may be present in a solid form. The cations may be present in a combination of two or more forms, including solvated cations, cations associated with bound anionic groups of the polymer electrolyte membrane, and cations bound in salt precipitates. The amount of salt added is typically between 0.001 and 0.5, more typically between 0.005 and 0.2, more typically between 0.01 and 0.1, and more typically between 0.02 and 0.05 charge equivalents based on the molar amount of acid functional groups present in the polymer electrolyte. Additional details regarding the combination of anionic copolymers with cerium, manganese or ruthenium cations can be found in U.S. Pat. Nos. 7,575,534 and 8,628,871, each to Frey et al.

Useful cerium oxide compounds may contain (IV) cerium in the oxidation state, (III) cerium in the oxidation state, or both, and may be crystalline or amorphous. The cerium oxide may be, for example, CeO ₂ Or Ce ₂ O ₃ . The cerium oxide may be substantially free of or may contain metallic cerium. The cerium oxide may be, for example, a thin oxidation reaction product on metallic cerium particles. The cerium oxide compound may or may not contain other metal elements. Examples of mixed metal oxide compounds including ceria include solid solutions (such as zirconia-ceria) and multiple groupsOxide compounds (such as barium cerate). While not wishing to be bound by theory, it is believed that the cerium oxide may strengthen the polymer by chelating and forming crosslinks between bound anionic groups. The amount of cerium oxide compound added is typically between 0.01 and 5 wt%, more typically between 0.1 and 2 wt%, and more typically between 0.2 and 0.3 wt%, based on the total weight of the copolymer. The cerium oxide compound is typically present in an amount of less than 1 volume percent, more typically less than 0.8 volume percent, and more typically less than 0.5 volume percent, relative to the total volume of the polymer electrolyte membrane. The cerium oxide may be particles of any suitable size, in some embodiments, particles of a size between 1nm and 5000nm, 200nm to 5000nm, or 500nm to 1000 nm. Additional details regarding polymer electrolyte membranes comprising cerium oxide compounds may be found in U.S. patent 8,367,267(Frey et al).

In some embodiments, the polymer electrolyte membrane may have a thickness of at most 90 microns, at most 60 microns, or at most 30 microns. Thinner membranes may provide less resistance to ion passage. This results in lower operating temperatures and greater available energy output in the use of the fuel cell. The thinner membrane must be made of a material that maintains its structural integrity in use.

In some embodiments, the copolymers of the present disclosure may be absorbed into a porous supporting matrix, typically in the form of a thin film having a thickness of at most 90 microns, at most 60 microns, or at most 30 microns. Any suitable method of absorbing the copolymer into the pores of the support matrix may be used, including overpressure, vacuum, wicking, and impregnation. In some embodiments, the copolymer is embedded in the matrix upon crosslinking. Any suitable support matrix may be used. Typically, the support matrix is non-conductive. Typically, the support matrix is comprised of a fluoropolymer, which is more typically perfluorinated. Typical substrates include porous Polytetrafluoroethylene (PTFE), such as biaxially stretched PTFE webs. In another embodiment, fillers (e.g., fibers) may be added to the polymer to reinforce the film.

For preparing the MEA, any combination may be usedGDLs are applied to either side of the CCM in a suitable manner. Any suitable GDL may be used to implement the present disclosure. Typically the GDL is constructed from a sheet comprising carbon fibers. Typically, the GDL is a carbon fiber construction selected from woven carbon fiber constructions and non-woven carbon fiber constructions. Carbon fiber constructions useful in practicing the present disclosure may include Toray ^TM Carbon paper, SpectraCarb ^TM Carbon paper, AFN ^TM Nonwoven carbon cloth and Zoltek ^TM And (3) carbon cloth. The GDL may be coated or impregnated with various materials, including carbon particle coating, hydrophilic treatment, and hydrophobic treatment, such as coating with Polytetrafluoroethylene (PTFE).

In use, an MEA according to the present disclosure is typically sandwiched between two rigid plates, referred to as distribution plates, also referred to as bipolar plates (BPP) or monopolar plates. Like the GDL, the distribution plate is typically electrically conductive. The distribution plate is typically made of a carbon composite, metal, or plated metal material. The distribution plate distributes reactant or product fluids to and from the MEA electrode surfaces, typically through one or more fluid-conducting channels scored, milled, molded, or embossed in one or more surfaces facing the MEA. These channels are sometimes referred to as flow fields. The distribution plate can distribute fluid back and forth between two successive MEAs in a stack, with one face directing fuel to the anode of the first MEA while the other face directs oxidant to the cathode of the next MEA (and removes product water), hence the term "bipolar plate". Alternatively, the distribution plate may have channels on only one side so that fluid is distributed back and forth only across the MEA on that side, which may be referred to as a "monopolar plate". A typical fuel cell stack includes several MEAs stacked alternately with bipolar plates.

Another type of electrochemical device is an electrolytic cell, which uses electricity to produce chemical changes or chemical energy. An example of an electrolytic cell is a chlor-alkali membrane cell, in which aqueous sodium chloride is electrolyzed by an electric current between an anode and a cathode. The electrolyte is separated into an anolyte portion and a catholyte portion by a membrane that is subjected to harsh conditions. In a chlor-alkali membrane cell, caustic sodium hydroxide is collected in the catholyte section, hydrogen gas is produced at the cathode section, and chlorine gas is produced from the sodium chloride-rich anolyte section at the anode. The copolymers of the present disclosure can be used, for example, to make catalyst inks and electrolyte membranes for use in chlor-alkali membrane cells or other electrolytic cells.

The copolymers according to the present disclosure may also be used as binders for electrodes in other electrochemical cells, such as lithium ion batteries. To prepare the electrode, the powdered active ingredient may be dispersed in a solvent with the copolymer and coated onto a metal foil substrate or current collector. The resulting composite electrode contains a powdered active ingredient in a polymeric binder that adheres to the metal substrate. Useful active materials for preparing the negative electrode include alloys of main group elements and conductive powders such as graphite. Examples of usable active materials for preparing the negative electrode include oxides (tin oxide), carbon compounds (e.g., artificial graphite, natural graphite, soil black lead, expanded graphite, and flake graphite), silicon carbide compounds, silicon oxide compounds, titanium sulfide, and boron carbide compounds. Useful active materials for preparing the positive electrode include lithium compounds, such as Li _4/3 Ti _5/3 O ₄ 、LiV ₃ O ₈ 、LiV ₂ O ₅ 、LiCo _0.2 Ni _0.8 O ₂ 、LiNiO ₂ 、LiFePO ₄ 、LiMnPO ₄ 、LiCoPO ₄ 、LiMn ₂ O ₄ And LiCoO ₂ . The electrode may also include a conductive diluent and an adhesion promoter.

An electrochemical cell comprising the copolymer disclosed herein as a binder can be made by placing at least one of the positive and negative electrodes in an electrolyte. In general, a microporous separator may be used to prevent the negative electrode from directly contacting the positive electrode. Once the electrodes are externally connected, lithiation and delithiation can occur at the electrodes, thereby generating an electrical current. A variety of electrolytes can be employed in lithium ion batteries. Representative electrolytes contain one or more lithium salts and a charge transport medium in solid, liquid or gel form. Examples of lithium salts include LiPF ₆ 、LiBF ₄ 、LiClO ₄ Lithium bis (oxalato) borate, LiN (CF) ₃ SO ₂ ) ₂ 、LiN(C ₂ F ₅ SO ₂ ) ₂ 、LiAsF ₆ 、LiC(CF ₃ SO ₂ ) ₃ And combinations thereof. Solid state charge transportExamples of transport media include polymeric media such as polyethylene oxide, polytetrafluoroethylene, polyvinylidene fluoride, fluorocopolymers, polyacrylonitrile, combinations thereof, and other solid media familiar to those skilled in the art. Examples of liquid charge transport media include ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, butylene carbonate, vinylene carbonate, fluoroethylene carbonate, fluoropropylene carbonate, gamma-butyrolactone, methyl difluoroacetate, ethyl difluoroacetate, dimethoxyethane, diglyme (bis (2-methoxyethyl) ether), tetrahydrofuran, dioxolane, combinations thereof, and other media familiar to those skilled in the art. Examples of charge transport media gels include those described in U.S. Pat. Nos. 6,387,570(Nakamura et al) and 6,780,544 (Noh). The electrolyte may contain other additives (e.g., co-solvents or redox chemical shuttles).

Electrochemical cells can be used as rechargeable batteries and in a variety of devices, including portable computers, tablet computer displays, personal digital assistants, mobile phones, motorized devices (e.g., personal or household appliances and vehicles), instruments, lighting devices (e.g., flashlights), and heating devices. One or more of the electrochemical cells may be combined to provide a battery.

Some embodiments of the present disclosure

In a first embodiment, the present disclosure provides a copolymer comprising:

of the formula- [ CF ] ₂ -CF ₂ ]-a bivalent unit of formula;

divalent units independently represented by the formula:

wherein a is 0 or 1, each b is independently 2 to 8, c is 0 to 2, e is 1 to 8, and each X is independently-F, -NZH, -NZSO ₂ (CF ₂ ) _1-6 SO ₂ X’、-NZ[SO ₂ (CF ₂ ) _d SO ₂ NZ] _1-10 SO ₂ (CF ₂ ) _d SO ₂ X ', or-OZ, wherein Z is independently hydrogen, an alkyl group having up to four carbon atoms, an alkali metal cation, or a quaternary ammonium cation, X' is independently-NZH or-OZ, and each d is independently 1 to 6; and

at least one divalent unit independently represented by the formula:

wherein A is-N (RF) ^a ) ₂ Or a non-aromatic 5-to 8-membered perfluorinated ring containing one or two nitrogen atoms in the ring and optionally at least one oxygen atom in the ring, each RF ^a Independently a linear or branched perfluoroalkyl group having 1 to 8 carbon atoms and optionally interrupted by at least one chain O or N atom, each Y independently being-H or-F, with the proviso that one Y may be-CF ₃ H is 0, 1 or 2, each i is independently 2 to 8, and j is 0, 1 or 2.

In a second embodiment, the present disclosure provides the copolymer according to the first embodiment, wherein b is 2 or 3, c is 0 or 1, and e is 4.

In a third embodiment, the present disclosure provides the copolymer according to the first embodiment, wherein b is 2 or 3, c is 1, and e is 2 or 4.

In a fourth embodiment, the present disclosure provides the copolymer of any one of the first to third embodiments, wherein a is

Wherein each RF is independently a perfluorinated alkylidene group having 2 to 4 carbon atoms, and D is a bond, -CF ₂ -, -O-, or-N-perfluoroalkyl.

In a fifth embodiment, the present disclosure provides the copolymer of any one of the first to fourth embodiments, wherein j is 1 or 2, and wherein a is

In a sixth embodiment, the present disclosure provides the copolymer of any one of the first to fifth embodiments, wherein a is N (RF) ^a ) ₂ Wherein each Rfa is independently a perfluoroalkyl group having up to four carbon atoms.

In a seventh embodiment, the present disclosure provides the copolymer of any one of the first to sixth embodiments, wherein h is 0.

In an eighth embodiment, the present disclosure provides the copolymer of any one of the first to seventh embodiments, wherein at least one of c is 1 or 2 or e is 3 to 8.

In a ninth embodiment, the present disclosure provides the copolymer of any one of the first to eighth embodiments, wherein a is 1.

In a tenth embodiment, the present disclosure provides the copolymer of any one of the first to eighth embodiments, wherein a is 0.

In an eleventh embodiment, the present disclosure provides the copolymer of any one of the first to tenth embodiments, wherein the copolymer further comprises at least one of divalent units derived from chlorotrifluoroethylene or divalent units derived from hexafluoropropylene.

In a twelfth embodiment, the present disclosure provides the copolymer of any one of the first to eleventh embodiments, wherein the copolymer has a T (a) of at most 105 ℃.

In a thirteenth embodiment, the present disclosure provides the copolymer of any one of the first to twelfth embodiments, wherein the copolymer further comprises divalent units independently represented by the formula:

wherein p is 0 or 1, q is 2 to 8, r is 0 to 2, s is 1 to 8, and Z' is hydrogen, an alkyl group having up to four carbon atoms, an alkali metal cation or a quaternary ammonium cation.

In a fourteenth embodiment, the present disclosure provides the copolymer of any one of the first to thirteenth embodiments, wherein the divalent units comprise at least 60 mole% of- [ CF ] based on the total amount of divalent units in the copolymer ₂ -CF ₂ ]-。

In a fifteenth embodiment, the present disclosure provides the copolymer of any one of the fourteenth embodiments, wherein at least a portion of the X groups are-OZ.

In a sixteenth embodiment, the present disclosure provides the copolymer of the fifteenth embodiment, wherein Z is hydrogen.

In a seventeenth embodiment, the present disclosure provides the copolymer of the fifteenth embodiment, wherein Z is sodium.

In an eighteenth embodiment, the present disclosure provides the copolymer of any one of the first to seventeenth embodiments, wherein the copolymer has an-SO in the range of 300 to 1200 ₂ X equivalent weight.

In a nineteenth embodiment, the present disclosure provides the copolymer of any one of the first to eighteenth embodiments, wherein the copolymer further comprises divalent units derived from at least one of ethylene, propylene, isobutylene, ethyl vinyl ether, vinyl benzoate, ethyl allyl ether, cyclohexyl allyl ether, norbornadiene, crotonic acid, alkyl crotonate, acrylic acid, alkyl acrylate, methacrylic acid, alkyl methacrylate, or hydroxybutyl vinyl ether.

In a twentieth embodiment, the present disclosure provides the method according to the first implementationThe copolymer of any of the embodiments through the nineteenth embodiment, wherein the copolymer has at most 100-COOM and-COF end groups/10 ⁶ Carbon atoms, wherein M is independently an alkyl group, a hydrogen atom, a metal cation, or a quaternary ammonium cation.

In a twenty-first embodiment, the present disclosure provides the copolymer of any one of the first to twentieth embodiments, wherein the copolymer comprises less than 25ppm of metal ions.

In a twenty-second embodiment, the present disclosure provides the copolymer of any one of the first to twenty-first embodiments, wherein the copolymer comprises-SO ₂ And (4) an X end group.

In a twenty-third embodiment, the present disclosure provides the copolymer of any one of the first to twenty-second embodiments, wherein the copolymer has a melt flow index of at most 40 grams per ten minutes measured at a temperature of 265 ℃ and a supported weight of 5 kg.

In a twenty-fourth embodiment, the present disclosure provides the copolymer of any one of the first to twenty-third embodiments, wherein the copolymer has a glass transition temperature of at most 20 ℃.

In a twenty-fifth embodiment, the present disclosure provides the copolymer of any one of the first to twenty-fourth embodiments, further comprising a copolymer of formula (la)

A divalent unit of formula (iv) wherein Rf is a linear or branched perfluoroalkyl group having 1 to 8 carbon atoms and optionally interrupted by one or more-O-groups, z is 0, 1 or 2, each n is independently 1,2, 3 or 4, and m is 0 or 1.

In a twenty-sixth embodiment, the present disclosure provides the copolymer of the twenty-fifth embodiment, wherein when a is 0, then n is not 3.

In a twenty-seventh embodiment, the present disclosure provides the copolymer of the twenty-fifth or twenty-sixth embodiment, wherein z is 1 or 2, and n is 1,2, or 3.

In a twenty-eighth embodiment, the present disclosure provides the copolymer of any one of the twenty-fifth to twenty-seventh embodiments, wherein at least one n is 1.

In a twenty-ninth embodiment, the present disclosure provides the copolymer of any one of the twenty-fifth to twenty-eighth embodiments, wherein the copolymer is represented by formula (la), based on the total moles of divalent units in the copolymer

The divalent units represented are present in a range of up to 20 mole% or up to 15 mole%, or in a range of 3 mole% to 20 mole%, or 4 mole% to 15 mole%.

In a thirtieth embodiment, the present disclosure provides the copolymer of any one of the first to twenty-ninth embodiments, wherein the total moles of divalent units in the copolymer are from

The divalent units represented are present in a range of up to 30 mole% or up to 25 mole%, or in a range of from 10 mole% to 30 mole%, or from 15 mole% to 25 mole%.

In a thirty-first embodiment, the present disclosure provides a polymer electrolyte membrane comprising the copolymer according to any one of the first to thirtieth embodiments.

In a thirty-second embodiment, the present disclosure provides the polymer electrolyte membrane of the thirty-first embodiment, wherein the polymer electrolyte membrane further comprises at least one of cerium cations, manganese cations, ruthenium cations, or cerium oxide.

In a thirty-third embodiment, the present disclosure provides the polymer electrolyte membrane of the thirty-second embodiment, wherein at least one of cerium cations, manganese cations, or ruthenium cations are present in a range of 0.2% to 20% relative to the amount of sulfonate groups in the copolymer.

In a thirty-fourth embodiment, the present disclosure provides a catalyst ink comprising the copolymer of any one of the first to thirtieth embodiments.

In a thirty-fifth embodiment, the present disclosure provides a membrane electrode assembly comprising at least one of the polymer electrolyte membrane of any one of the thirty-first to thirty-third embodiments or the catalyst ink of the thirty-fourth embodiment.

In a thirty-sixth embodiment, the present disclosure provides a binder for an electrode, the binder comprising the copolymer of any one of the first to thirty-first embodiments.

In a thirty-seventh embodiment, the present disclosure provides an electrochemical cell comprising the binder of the thirty-sixth embodiment.

In order that the disclosure may be more fully understood, the following examples are set forth. It should be understood that these examples are for illustrative purposes only and are not to be construed as limiting this disclosure in any way.

Examples

Unless otherwise stated or apparent, all materials are commercially available (e.g., from Aldrich Chemical Company, st. louis, Mo.) or are known to those skilled in the art.

The following abbreviations are used in this section: g ═ L, cm ═ cm, mm ═ mm, min ═ min, h ═ h, NMR ═ nuclear magnetic resonance, ° c ═ celsius, K ═ kelvin, rpm ═ rpm, MPa ═ megapascal. Abbreviations for materials used in this section, as well as descriptions of materials, are provided in table 1.

In the following examples, 2,2,3,3,5,5,6, 6-octafluoro-4- [1,1,2,2,3,3, -hexafluoro-3- (1,2, 2-trifluoroethyleneoxy) propyl ] is prepared generally as described in example 2 of U.S. patent application publication No. 2014/0130713 (Costello et al)]Morpholine (MV3c4 NO). F was prepared according to the method described in U.S. Pat. No. 6,624,328(Guerra) ₂ C＝CF-O-CF ₂ CF ₂ CF ₂ CF ₂ SO ₂ F (MV 4S). APS is ammonium persulfate, commercially available from Sigma Aldrich (Sigma Aldrich). FE1 is CF ₃ -O-CF ₂ CF ₂ CF ₂ -O-CHFCF ₂ -COONH ₄ And based on CF ₃ -O-CF ₂ CF ₂ CF ₂ -O-CHFCF ₂ -COONH ₄ 1.5 wt% FC-70 in a 30% aqueous solution. CF was prepared as described in U.S. Pat. No. 7,671,112 (Hintzer et al) ₃ -O-CF ₂ CF ₂ CF ₂ -O-CHFCF ₂ -COONH ₄ . FC-70 is a fluid commercially available from 3M Company, St Paul, MN, St, under the trade designation "FLUORINERT FC-70".

Example 1

Part A

355g of distilled water, 19g of FE1, 143g of MV4S and 84g of MV3c4NO were added to a 1L flask. The liquid was mixed at about 200rpm for about 15 minutes at room temperature using an overhead stirrer equipped with propeller blades. The resulting emulsion was used as prepared.

Part B

A4L reactor was charged with 2000g of distilled water. After the liquid was brought to a temperature of 65 ℃, a charge of FE1(48g), APS (5.2g), part a (75g), ammonium hydroxide (4.26g of a 28% w/w aqueous solution) and additional distilled water (400g) was added with stirring (450 rpm). Immediately following this addition, the vacuum was broken with nitrogen to 0psig (0 MPa). The reactor was then pressurized with TFE until the reactor reached a pressure of 145psig (1.10 MPa). Once under pressure, part A (500g) and TFE were added in a weight ratio of 4.76 (part A: TFE). The reaction was run until 11.4% solids was reached, the reaction was stopped, and the latex was discharged from the reactor. A portion of the resulting dispersion was coagulated by freezing and subsequent thawing, and the isolated solid polymer was dried at 130 ℃ for 16 hours. The equivalent weight was 983, calculated according to the following equation.

Example 2

Part A

355g of distilled water, 19g of FE1, 220g of MV4S and 32g of MV3c4NO were added to a 1L flask. The liquid was mixed at about 200rpm for about 15 minutes at room temperature using an overhead stirrer equipped with propeller blades. The resulting emulsion was used as prepared.

Part B

A4L reactor was charged with 2000g of distilled water. After the liquid was brought to a temperature of 65 ℃, a charge of FE1(48g), APS (5.2g), part a (75g), ammonium hydroxide (4.26g of a 28% w/w aqueous solution) and additional distilled water (400g) was added with stirring (450 rpm). Immediately following this addition, the vacuum was broken with nitrogen to 0psig (0 MPa). The reactor was then pressurized with TFE until the reactor reached a pressure of 145psig (1.10 MPa). Once under pressure, part A (500g) and TFE were added in a weight ratio of 3.12 (part A: TFE). The reaction was run until 14.7% solids was reached, the reaction was stopped, and the latex was discharged from the reactor. A portion of the resulting dispersion was coagulated by freezing and subsequent thawing, and the isolated solid polymer was dried at 130 ℃ for 16 hours. The equivalent weight is 822, calculated according to the equation below.

Terpolymer composition

Use of ¹⁹ F-NMR spectroscopy was performed to confirm the composition of purified examples 1 and 2. Spectra were collected at 180 ℃ at 17kHz MAS on a Varian 400MHz NMRS solid state NMR spectrometer (Varian Medical Systems; Palo Alto, Calif., USA) equipped with a 3.2mm Varian MAS probe. The components are presented in table 1.

TABLE 1 compositions of example 1 and example 2

Equivalent Weight (EW)

The EW of the copolymer of TFE, sulfonyl fluoride monomer (M2) and nitrogen-containing monomer (M3) can be calculated from the following formula:

glass transition temperature

The glass transition temperature (Tg) of the polymer samples can be measured using a TA Instruments Q2000 DSC. The sample may be heated at 10 ℃ per minute on a temperature ramp of-50 ℃ to about 200 ℃. The transition temperature was analyzed on the second heating.

Oxygen Transmission Rate (OTR) analysis

The coated film was masked to 5cm using an adhesive backed aluminum mask (TM Electronics, Inc., Davens, Mass., PML-800815) to form a 5cm mask ² Area (both sides masked) and then cut a 4 inch (10.2cm) diameter circular sample using an AccuCut mold and an AccuCut MARK IV machine press (Omaha, NE, nebraska). A mask is first applied to the open side of the film with one side of the film against the release liner substrate coated thereon. A weighted roller is used to exert a force on the mask to ensure a good seal around the active area of the sample. The release liner was then removed and the second mask was applied in registration with the first mask and the weighted roller was again used to ensure a good seal between the mask and the sample. With N ₂ 88.6ppm O in calibration gas (Oxygen Services Company, SG 300 LG025, certified, san Paul, Minn.) Oxygen Services Company, SG 300 LG025, certified, St. Paul, MN) ₂ An oxygen permeability analyzer (8001L oxygen permeability analyzer, Systech Illinois Instruments Company, Johnsburg, IL) was calibrated, or a membrane with certified Oxygen Transmission Rate (OTR) values. After vacuum grease lubrication (Manchester Abies, Man, England)hester, UK)) was applied to the periphery of each cell, a mask sample was installed into the cell, two samples per test run, to ensure a good seal between the sample and the nitrogen side of the instrument. Ultra-high purity Oxygen (99.996%, Oxygen Services Company, SG 300 MG003) test and ultra-high purity nitrogen (99.999%, Oxygen Services Company, NIT 304UHP) carrier gas was obtained from Oxygen Services Company. The measurement is started after the line is purged and leak checked to ensure the cell is properly sealed. The permeation rate was sampled at 20 minute intervals and the test was stopped when the instrument determined a 1% or less change in OTR between sampling intervals. The OTR value was from 1 atm using the thickness of the sample and the oxygen partial pressure difference from the test to the carrier gas side

Is converted into

Each sample was assigned a test temperature.

Film coating method

The film of material was coated using an Automatic Film Applicator (AFA)1132N stretcher (TCQ Sheen, Metamora, MI) set at a speed of 50 mm/sec for the full length coating distance. On the drawframe coated surface was placed a glass plate (12"× 17" × 1/8",30.5cm × 43.2cm × 0.32cm) and a 2mil (51 micron) silicone coated PET release liner (7100, north carolina carley resistance corporation (Loparex, Cary, NC)) or a 2mil polytetrafluoroethylene sheet (TVF 002-R-24, Plastics International, Eden Prairie, MN). The glass and any debris of the liner were cleaned with isopropyl alcohol (IPA). Both the release liner and the plate are secured under the draft mechanism by a built-in clip. A 4 inch (10.2cm) milled coating notch bar (Paul n gardner company of Pompano bidggard, florida, Gardco, Paul n gardner co., Pompano Beach, FL)) was placed on the silicone coated PET release liner, the ionomer dispersion was poured into the front of the notch bar, and the ionomer dispersion was coated at a set speed and distance. The release liners were adhered at the four corners so that they did not lift in the forced air oven. The glass plate with release liner and coating was pulled from the draw frame, covered with an aluminum pan to prevent chips from falling into the coating, and placed on a ceramic rack in a Despatch blast oven (Despatch, Minneapolis, MN) set at 120 ℃ for 30 minutes. The release liner and the coating thereon were removed from the glass, placed in an aluminum pan, covered with another aluminum pan, and then placed back in the oven at a setting of 140 ℃ for 15 minutes. The temperature was raised to 160 ℃ for 10 minutes. The film was cooled and characterized by micrometer measurements.

Dynamic Mechanical Analysis (DMA) for Talpha assay

The modulus of elasticity of the film samples in tensile mode was measured using a TA Instruments DMA Q800 at 1Hz (6.28 rad/sec). The membrane samples to be tested were vacuum dried overnight at 50C-60C and stored on molecular sieves in closed containers or desiccators until tested. The film is removed from the dryer and quickly cut into the desired geometry. A typical thin rectangular strip sample, approximately 6.7mm wide and 30-60 um thick, is mounted in a jig and tightened at a length of approximately 6-10 mm. The pre-treatment of the sample in the instrument included a temperature increase from room temperature to 70 ℃ at 5C/min, a 5 minute isothermal hold, and a rapid temperature increase to 20 ℃ to-50 ℃ and hold until equilibrium was reached. The analysis was performed using 15um amplitude strain at 1Hz and 0.01N pre-stress from the equilibrium temperature between 20 ℃ to-50 ℃ to the temperature at which the sample developed (typically below 200 ℃). The elastic modulus E' and loss modulus E "were measured. Talpha is determined at the tan-delta maximum before yielding, i.e., the ratio of E "/E'.

Reagent：

The product containing lioh.h may be obtained by Sigma Aldrich (Sigma-Aldrich) ₂ O and Li ₂ CO ₃ The reagent of (1).

Hydrolysis and dispersion of example 1:

175g of example 1 and (30.8g) LiOH ₂ O、(30.8g)Li ₂ CO ₃ And 1500g of deionized water were added to a 2 gallon stirred pressure reactor (Parr Instrument Company, Moline, IL). The vessel was stirred and held for 1 hour to 255 ℃ and cooled to room temperature with stirring. The resulting dispersion was filtered through a 1um glass fiber syringe filter (4524T, Port Washington, N.Y.) and passed through an Amberlite resin approximately (2.4mol acid sites) packed polycarbonate column (2.55cm (r) x 65cm (h)). Prior to ion exchange of the polymer dispersion, 20L of DI H was used ₂ And O, washing the resin. The ionomer dispersion and system wash were passed through the resin once and the pH 0-1 (colorimetric pH indicator strip, 8880-1, richca Chemical Co, Arlington, TX) dispersion was collected. The acidic polymer was collected and dried in a forced air oven to remove water at about 70 ℃ to obtain 112.3g of a clear solid.

Coating Dispersion of example 1：

Approximately 9.4g of example 1 was dispersed in 13g of 60/40nPA/H by rolling in a 125mL plastic bottle and increasing the agitation with a stir bar until dispersed ₂ The coating dispersion was prepared in O (w/w) solvent. After heating the small sample on an aluminum pan at 150 ℃ for 10 minutes, the dispersion solids were determined gravimetrically to be 39.16 wt%.

Film of example 1

Films from the coating dispersions of example 1 were prepared according to the above film coating method to obtain films of 34um-39um thickness over the entire coating. The membrane was analyzed by the Talpha method by DMA to determine that Talpha was 101.6 ℃. Another 35um-36um thick film was prepared and the oxygen permeability was determined by the OTR assay described above and found to be 4.5181X 10 ^-15 mol cm cm ^-2 s ^-1 kpa ^-1 。

Hydrolysis and Dispersion of example 2：

250g of example 2 and (44.3g) LiOH ₂ O、(45.2g)Li ₂ CO ₃ And 1500g of deionized water were added to a 4L Parr stirred reactor. The vessel was stirred and held for 1 hour to 255 ℃ and cooled to room temperature with stirring. The resulting dispersion was filtered through a 1um glass fiber syringe filter (4524T, Port Washington, N.Y.) and passed through an Amberlite resin approximately (2.4mol acid sites) packed polycarbonate column (2.55cm (r) x 65cm (h)). Prior to ion exchange of the polymer dispersion, 20L of DI H was used ₂ And O, washing the resin. The ionomer dispersion and system wash were passed through the resin once and the pH 0-1 (colorimetric pH indicator strip, 8880-1, richca Chemical Co, Arlington, TX) dispersion was collected. The acidic aqueous polymer dispersion was collected and dried in a PTFE sheet-lined glass dish in a forced air oven to remove water at about 70 ℃ to obtain 168.74g of a transparent solid.

Coating Dispersion of example 2：

Approximately 9g of example 1 was dispersed in 13g of 60/40nPA/H by rolling in a 125mL plastic bottle and increasing the agitation with a stir bar until dispersed ₂ The dispersion was prepared in O (w/w) solvent. After heating the small sample on an aluminum pan at 150 ℃ for 10 minutes, the dispersion solids were determined gravimetrically to be 39.48 wt%.

Film of example 2

Films of the coating dispersions from example 2 were prepared according to the above film coating method to obtain films about 57um thick. The Talpha method of analyzing the film by DMA determined that Talpha is 99.5 ℃. Another 36um thick film was prepared and the oxygen permeability was determined by the OTR assay described above to be 4.53256X 10 ^-15 mol cm cm ^-2 s ^-1 kpa ^-1 。

Various modifications and alterations of this disclosure may be made by those skilled in the art without departing from the scope and spirit of this disclosure, and it should be understood that this invention is not to be unduly limited to the illustrative embodiments set forth herein.

Claims

1. A copolymer, the copolymer comprising:

of the formula- [ CF ] ₂ -CF ₂ ]-a bivalent unit of formula;

at least one divalent unit independently represented by the formula:

at least one divalent unit independently represented by the formula:

2. The copolymer of claim 1, wherein b is 2 or 3, c is 0 or 1, and e is 2 to 4.

3. The copolymer of claim 1 or 2, wherein X is-F or-OZ.

4. The copolymer of any one of claims 1 to 3, wherein A is

5. The copolymer of any one of claims 1 to 4, wherein j is 1 or 2, and wherein A is

6. The copolymer of any one of claims 1 to 5, wherein when Z is-F, the copolymer has a glass transition temperature of at most 20 ℃.

7. The copolymer of any one of claims 1 to 6, further comprising at least one divalent unit represented by the formula:

wherein Rf is a linear or branched perfluoroalkyl group having 1 to 8 carbon atoms and optionally interrupted by one or more-O-groups, z is 0, 1 or 2, each n is independently 1,2, 3 or 4, and m is 0 or 1.

8. The copolymer of any one of claims 1 to 7, wherein the copolymer further comprises at least one of divalent units derived from chlorotrifluoroethylene or divalent units derived from hexafluoropropylene.

9. The copolymer of any one of claims 1 to 8, wherein when Z is hydrogen, the copolymer has a T (a) of at most 105 ℃.

10. The copolymer of any one of claims 1 to 9, wherein the copolymer has an-SO in the range of 300 to 1200 ₃ Z equivalent weight.

11. The copolymer of any one of claims 1 to 10, wherein the copolymer is represented by formula (la), based on the total moles of divalent units in the copolymer

The divalent units represented are present in the range of 0.5 to 20 mole%.

12. The copolymer of any one of claims 1 to 11, wherein the copolymer is represented by formula (la) based on the total moles of divalent units in the copolymer

The represented divalent units are present in the range of 10 to 30 mol%.

13. A catalyst ink comprising the copolymer according to any one of claims 1 to 12.

14. A polymer electrolyte membrane prepared from the copolymer according to any one of claims 1 to 12.

15. A membrane electrode assembly comprising at least one of the catalyst ink of claim 13 or the polymer electrolyte membrane of claim 14.